American DG Energy (ADGE) 10-K 31 Mar 15 2013 FY Annual report Financial data

DOCUMENT_AND_ENTITY_INFORMATIO

DOCUMENT AND ENTITY INFORMATION (USD $)	12 Months Ended
	Dec. 31, 2014	Mar. 30, 2015	Jun. 30, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	AMERICAN DG ENERGY INC
Entity Central Index Key	1378706
Current Fiscal Year End Date	-19
Entity Filer Category	Smaller Reporting Company
Trading Symbol	adge
Entity Common Stock, Shares Outstanding		50,669,648
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2013
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$55,927,933

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2014	Dec. 31, 2013
ASSETS
Cash and cash equivalents	$11,825,915	$9,804,291
Accounts receivable, net	1,140,811	988,420
Unbilled revenue	12,533	12,765
Due from related party	39,682	304,288
Inventory	1,153,927	2,246,335
Prepaid and other current assets	852,069	196,939
Total current assets	15,024,937	13,553,038
Property, plant and equipment, net	24,885,155	21,931,289
Accounts receivable, long-term	3,600	45,200
Other assets, long-term	92,148	54,768
TOTAL ASSETS	40,005,840	35,584,295
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accounts payable	605,530	871,079
Accrued expenses and other current liabilities	485,570	622,568
Due to related party	630,805	178,216
Total current liabilities	1,721,905	1,671,863
Long-term liabilities:
Convertible debentures	1,645,444	1,800,000
Convertible debentures due related parties	15,864,215	19,898,380
Warrant liability	6,780	132,265
Notes Payable, Related Parties	3,000,000	0
Other long-term liabilities	2,227	15,876
Total liabilities	22,240,571	23,518,384
Stockholders’ equity:
Common stock, $0.001 par value; 100,000,000 shares authorized; 52,140,001 and 49,817,920 issued and outstanding at December 31, 2014 and 2013, respectively	52,140	49,818
Additional paid-in capital	49,854,998	40,110,305
Accumulated deficit	-35,232,411	-29,343,517
Total American DG Energy Inc. stockholders’ equity	14,674,727	10,816,606
Noncontrolling interest	3,090,542	1,249,305
Total stockholders’ equity	17,765,269	12,065,911
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$40,005,840	$35,584,295

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Common stock, par value (usd per share)	$0.00	$0.00
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	52,140,001	49,817,920
Common stock, shares outstanding	52,140,001	49,817,920

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Revenues
Energy revenues	$7,808,933	$7,164,226
Turnkey & other revenues	758,620	297,654
Sales Revenue, Net, Total	8,567,553	7,461,880
Cost of sales
Fuel, maintenance and installation	5,914,525	4,862,905
Non-cash site impairments	723,438	0
Depreciation expense	1,843,817	1,382,693
Cost of Goods and Services Sold, Total	8,481,780	6,245,598
Gross profit	85,773	1,216,282
Operating expenses
General and administrative	3,238,141	2,940,833
Selling	1,078,351	1,383,077
Engineering	897,445	1,018,914
Operating Expenses, Total	5,213,937	5,342,824
Loss from operations	-5,128,164	-4,126,542
Other income (expense)
Interest and other income	92,928	49,291
Interest expense	-1,402,493	-1,292,766
Debt conversion inducement expense	-324,977	0
Loss on extinguishment of debt	-533,177	0
Change in fair value of warrant liability	125,485	257,189
Nonoperating Income (Expense), Total	-2,042,234	-986,286
Loss before benefit (provision) for income taxes	-7,170,398	-5,112,828
Benefit/(Provision) for income taxes	645,040	-13,450
Consolidated net loss	-6,525,358	-5,126,278
Loss attributable to noncontrolling interest	636,464	239,606
Net loss attributable to American DG Energy Inc.	($5,888,894)	($4,886,672)
Net loss per share - basic and diluted (usd per share)	($0.12)	($0.10)
Weighted average shares outstanding - basic and diluted (in shares)	50,999,408	48,932,838

CONSOLIDATED_STATEMENTS_OF_STO

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $)	Total	Common Stock $0.001 Par Value	Additional Paid-in Capital	Accumulated Deficit	Noncontrolling Interest
Balance, Beginning Balance at Dec. 31, 2012
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Distributions to noncontrolling interest	($311,664)				($311,664)
Ownership changes to noncontrolling interest	559,500				559,500
Sale of common stock, net of costs	952,333	634	951,699
EuroSite stock dividend to American DG Energy investors	0		-199,408		199,408
Non-cash debt discount (Issuance of subsidiary common stock in conjunction with prepayment of interest on and exchange of convertible debentures)	0
Conversion of convertible debenture interest to common stock	1,170,051	693	1,169,358
Conversion of subsidiary convertible debentures into subsidiary common stock	0
Stock based compensation expense	596,349		538,217		58,132
Exercise of stock options	0
Fair value of conversion option	649,000		649,000
Net loss	-5,126,278			-4,886,672	-239,606
Balance, Ending Balance at Dec. 31, 2013	12,065,911	49,818	40,110,305	-29,343,517	1,249,305
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Distributions to noncontrolling interest	-258,289				-258,289
Noncontrolling interest share of transactions affecting subsidiary ownership	-124,056		-2,718,159		2,594,103
Ownership changes to noncontrolling interest			4,704,500
Sale of common stock, net of costs	3,269,275	2,650	3,266,625
Non-cash debt discount (Issuance of subsidiary common stock in conjunction with prepayment of interest on and exchange of convertible debentures)	4,207,411		4,122,500		84,911
Conversion of convertible debenture interest to common stock of subsidiary	582,000		582,000
Sale of subsidiary common stock, net of costs	1,486,329		1,486,329
Conversion of convertible debenture interest to common stock	624,368	260	624,108
Share repurchase program	-450,696	-588	-450,108
Reacquisition by subsidiary of common stock	-42,902		-42,902
Conversion of subsidiary convertible debentures into subsidiary common stock	2,455,377		2,455,377
Stock based compensation expense	475,899		418,923		56,976
Net loss	-6,525,358			-5,888,894	-636,464
Balance, Ending Balance at Dec. 31, 2014	$17,765,269	$52,140	$49,854,998	($35,232,411)	$3,090,542

CONSOLIDATED_STATEMENTS_OF_STO1

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY Parenthetical (USD $)	Dec. 31, 2014	25-May-14	Dec. 31, 2013	Nov. 25, 2013	25-May-13
Statement of Stockholders' Equity [Abstract]
Common Stock, $0.001 Par Value	$0.00	$2.24	$0.00	$1.54	$1.84

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	($5,888,894)	($4,886,672)
Loss attributable to noncontrolling interest	-636,464	-239,606
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,888,102	1,471,914
Loss on extinguishment of debt	533,177	0
Non-cash site impairments	723,438	0
Provision for losses on accounts receivable	49,322	235,638
Amortization of deferred financing costs	48,176	10,224
Decrease in fair value of warrant liability	-125,485	-257,189
Non-cash interest expense	1,210,086	1,170,051
Stock-based compensation	475,899	596,349
Non-cash debt conversion inducement expense	324,977	0
Changes in operating assets and liabilities:
Accounts receivable and unbilled revenue	-159,881	-454,053
Due from related party	264,606	-285,916
Inventory	1,092,408	674,109
Prepaid and other current assets	-798,263	93,449
Increase (decrease) in:
Accounts payable	-265,549	105,461
Accrued expenses and other current liabilities	20,610	90,148
Due to related party	452,589	136,404
Other long-term liabilities	8,486	-13,568
Net cash used in operating activities	-782,660	-1,553,257
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	-5,649,433	-5,590,055
Net cash used in investing activities	-5,649,433	-5,590,055
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of convertible debentures	1,450,000	2,947,380
Proceeds from sale of common stock, net of costs	3,269,275	952,333
Proceeds from sale of subsidiary common stock, net of costs	1,486,329	0
Proceeds from note payable related party loan to subsidiary	3,000,000	0
Purchases of common stock, net of costs	-450,696	0
Share repurchases by subsidiary	-42,902	0
Principal payments on capital lease obligations	0	-3,365
Distributions to noncontrolling interest	-258,289	-311,664
Net cash provided by financing activities	8,453,717	3,584,684
Net increase (decrease) in cash and cash equivalents	2,021,624	-3,558,628
Cash and cash equivalents, beginning of the period	9,804,291
Cash and cash equivalents, end of the period	11,825,915	9,804,291
Supplemental disclosures of cash flows information:
Income taxes	59,317	68,762
Interest	131,367	115,635
Non-cash investing and financing activities:
Interest on convertible debentures paid in stock of subsidiary	585,718	0
Conversion of convertible debenture interest into common stock	624,368	1,164,000
Convertible debenture interest adjustment	0	6,051
Conversion of subsidiary convertible debentures into subsidiary common stock	2,455,377	0
Fair value of warrant exchanged for future convertible debenture interest	84,911	0
Non-cash debt discount (Issuance of subsidiary common stock in conjunction with prepayment of interest on and exchange of convertible debentures)	$4,207,411	$0

The_Company

The Company	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
The Company	The Company:
	American DG Energy Inc., or the Company, we, our or us, distributes, owns, operates and maintains clean, on-site energy systems that produce electricity, hot water, heat and cooling. The Company's business model is to own the equipment that it installs at customers' facilities and to sell the energy produced by these systems to its customers on a long-term contractual basis at prices guaranteed to the customer to be below conventional utility rates. The Company calls this business the American DG Energy “On-Site Utility”.
	The Company was incorporated as a Delaware corporation on July 24, 2001 to install, own, operate and maintain complete DG systems, or energy systems, and other complementary systems at customer sites and sell electricity, hot water, heat and cooling energy under long-term contracts at prices guaranteed to the customer to be below conventional utility rates.
	The Company derives revenues from selling energy in the form of electricity, heat, hot water and cooling to its customers under long-term energy sales agreements (with a typical term of 10 to 15 years). The energy systems are generally owned by the Company and are installed in its customers’ buildings. Each month the Company obtains readings from energy meters to determine the amount of energy produced for each customer. The Company multiplies these readings by the appropriate published price of energy (electricity, natural gas or oil) from its customers’ local energy utility, to derive the value of its monthly energy sale, less the applicable negotiated discount. The Company’s revenues per customer on a monthly basis vary based on the amount of energy produced by its energy systems and the published price of energy (electricity, natural gas or oil) from its customers’ local energy utility that month. The Company’s revenues commence as new energy systems become operational. As of December 31, 2014, the Company had 123 energy systems operational. In some cases the customer may choose to own the system rather than have it owned by American DG Energy.

Summary_of_significant_account

Summary of significant accounting policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Summary of significant accounting polcies	Summary of significant accounting policies:
	Principles of Consolidation and Basis of Presentation:
	The accompanying consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) and include the accounts of the Company and entities in which it has a controlling financial interest. Those entities include the Company's 51.0% joint venture, American DG New York, LLC, or ADGNY, and its 50.1% owned subsidiary EuroSite Power Inc., or EuroSite Power. The interests in underlying energy system projects in the joint venture vary between the Company and its joint venture partner. As the controlling partner, all major decisions in ADGNY are made by the Company according to the joint venture agreement. Distributions, however, are made based on the economic ownership. The economic ownership is calculated by the amount invested by the Company and the noncontrolling partner in each site. Each quarter the Company calculates a year-to-date profit/loss for each site that is part of ADGNY and the noncontrolling interest percent ownership in each site is applied to determine the noncontrolling interest share in the profit/loss. The Company follows the same calculation regarding available cash and a cash distribution is made to the noncontrolling interest partner each quarter. On the Company’s balance sheet, noncontrolling interest represents the partner’s investment in the entity, plus its share of after tax profits less any cash distributions. The Company owned a controlling 51.0% legal interest and had a 62.5% economic interest in ADGNY as of December 31, 2014.
	As of December 31, 2014 and December 31, 2013, the Company owned a 50.1% and a 70.7%, interest in EuroSite Power, respectively, and has consolidated EuroSite Power into its financial statements in both years in accordance with GAAP.
	The Company has consolidated the operating results and financial position of EuroSite Power as it has determined it has a controlling financial interest in EuroSite Power. This determination was based on application of the variable interest entity (VIE) model which determines whether a controlling financial interest exists by other than majority voting ownership. In applying the VIE model, the Company considered the explicit and implicit variable interests which exist in EuroSite Power including its own and its ability to direct the activities of EuroSite Power which most significantly effect it’s economic performance and the Company’s obligation to absorb the expected losses of EuroSite Power.  In addition to its equity ownership in EuroSite Power, the Company has an implicit variable interest in EuroSite Power through its guarantee of the long term convertible indebtedness of EuroSite Power. This results in the Company’s voting ownership being disproportional to its obligation to absorb the expected losses of EuroSite Power. This combined with the fact that substantially all of EuroSite Power’s  activities either involve or are conducted on behalf of the Company results in EuroSite Power being considered a VIE.
	The current level of the Company’s ownership results in the Company’s ability to control the activities which most significantly effect the economic performance of EuroSite  Power. This combined with the Company’s obligation to absorb losses which could be significant to EuroSite Power qualify the Company as the primary beneficiary of EuroSite Power. As the primary beneficiary of a VIE, the Company is required to consolidate the operating results and financial position of the VIE.
	On July 2, 2013, the Company declared a special dividend of one share of EuroSite Power common stock for every ten shares of American DG Energy common stock (“special dividend”). The special dividend was paid on August 15, 2013, to stockholders of record as of the close of business on July 25, 2013. In connection with this transaction, the Company issued to its stockholders an aggregate of 4,880,679 shares of EuroSite Power common stock that it owns.
	The Company provides a guarantee with respect to the outstanding third party convertible indebtedness under EuroSite Power’s convertible debentures which it was not contractually obligated to provide. During 2013, the Company loaned $1,100,000 to EuroSite Power which it was not contractually obligated to do. The loan was made to facilitate deployment of new energy systems and the loan was ultimately converted into common stock of EuroSite Power. The Company also helps facilitate and assists EuroSite Power in obtaining additional sources of financing.
	The Company’s operations are comprised of one business segment. The Company’s business is selling energy in the form of electricity, heat, hot water and cooling to its customers under long-term sales agreements. The Company’s revenue is generated in the United States of America and in the United Kingdom. During the years ended December 31, 2014 and 2013 revenue generated in the United States amounted to $6,989,680 and $6,623,001, respectively, and revenue generated in the United Kingdom amounted to $1,577,873 and $838,879 respectively.  At December 31, 2014, $18,536,250 of the Company’s long lived assets were located in the United States of America and $6,348,905 were located in the United Kingdom.  At December 31, 2013, $17,900,959 of the Company’s long lived assets were located in the United States of America and $4,030,330 were located in the United Kingdom.
	The Company has experienced total net losses since inception of approximately $35.2 million. For the foreseeable future, the Company expects to experience continuing operating losses and negative cash flows from operations as its management executes the current business plan. The Company believes that its existing resources, including cash and cash equivalents and future cash flow from operations, are sufficient to meet the working capital requirements of its existing business for the foreseeable future, including the next twelve months; however, as the Company continues to grow its business by adding more energy systems, the cash requirements will increase. Beyond March 31, 2016, the Company may need to raise additional capital through a debt financing or an equity offering to meet its operating and capital needs. There can be no assurance, however, that the Company will be successful in its fundraising efforts or that additional funds will be available on acceptable terms, if at all.
	In 2014, the Company raised $8,453,717, net of issuance costs, share repurchases and distributions, from the sale of the Company and its subsidiary's common stock, its subsidiaries loans and convertible debt. If the Company is unable to raise additional capital in 2016 it may need to terminate certain of its employees and adjust its current business plan. Financial considerations may cause the Company to modify planned deployment of new energy systems and may decide to suspend installations until it is able to secure additional working capital. The Company will evaluate possible acquisitions of, or investments in, businesses, technologies and products that are complementary to its business; however, the Company is not currently engaged in such discussions.
	Use of Estimates
	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
	Revenue Recognition
	Revenue from energy contracts is recognized when electricity, heat, and chilled water is produced by the cogeneration systems on-site. The Company bills each month based on various meter readings installed at each site. The amount of energy produced by on-site energy systems is invoiced, as determined by a contractually defined formula. Under certain energy contracts, the customer directly acquires the fuel to power the systems and receives credit for that expense from the Company. The credit is recorded as a cost of sale. Revenues from operations, including shared savings are recorded when provided and verified. Maintenance service revenue is recognized over the term of the agreement and is billed on a monthly basis in arrears.
	In some cases, the customer may choose to own the energy system rather than have it owned by American DG Energy. In this case, the Company accounts for revenue, or turnkey revenue, and costs using the percentage-of-completion method of accounting. Under the percentage-of-completion method of accounting, revenues are recognized by applying percentages of completion to the total estimated revenues for the respective contracts. Costs are recognized as incurred. The percentages of completion are determined by relating the actual cost of work performed to date to the current estimated total cost at completion of the respective contracts. When the estimate on a contract indicates a loss, the Company records the entire expected loss, regardless of the percentage of completion. The excess of contract costs and profit recognized to date on the percentage-of-completion accounting method in excess of billings is recorded as unbilled revenue. Billings in excess of related costs and estimated earnings is recorded as deferred revenue.
	Customers may buy out their long-term obligation under energy contracts and purchase the underlying equipment from the Company. Any resulting gain on these transactions is recognized over the payment period in the accompanying consolidated statements of operations.
	The Company is able to participate in the demand response market and receive payments due to the availability of its energy systems. Demand response programs provide payments for either the reduction of electricity usage or the increase in electricity production during periods of peak usage throughout a utility territory. For the year ended December 31, 2014 and 2013, the revenue recognized from demand response activity was $247,518 and $112,405, respectively.
	Cash and Cash Equivalents
	The Company considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. The Company has cash balances in certain financial institutions in amounts which occasionally exceed current federal deposit insurance limits. The financial stability of these institutions is continually reviewed by senior management. The Company believes it is not exposed to any significant credit risk on cash and cash equivalents.
	Concentration and Credit Risk
	Financial instruments, which potentially subject the Company to concentrations of credit risk, consist of highly liquid cash equivalents and trade receivables. The Company’s cash equivalents are placed with certain financial institutions and issuers. As of December 31, 2014, the Company had a balance of $10,771,457 in cash and cash equivalents that exceeded the Federal Deposit Insurance Corporation limit.
	During the years ended December 31, 2014 and 2013, one customer accounted for 11.0% and 12.0% of revenue, respectively.
	Accounts Receivable
	The Company maintains receivable balances primarily with customers located throughout New York, New Jersey and the United Kingdom. The Company reviews its customers’ credit history before extending credit and generally does not require collateral. An allowance for doubtful accounts is established based upon factors surrounding the credit risk of specific customers, historical trends and other information. Generally, such losses have been within management’s expectations. Bad debt is written off when identified.
	At December 31, 2014 and 2013, the allowance for doubtful accounts was $112,000 and $183,201, respectively. Included in accounts receivable are amounts from four major customers accounting for approximately 27.0% and 35.0% of total accounts receivable for the years ended December 31, 2014 and 2013, respectively.
	Inventory
	Inventories are stated at the lower of cost or market, valued on a first-in, first-out basis. Inventory is reviewed periodically for slow-moving and obsolete items. As of December 31, 2014 and 2013, there were no reserves or write-downs recorded against inventory.
	Supply Concentrations
	Most of the Company’s cogeneration unit purchases for the years ended December 31, 2014 and 2013 were from one vendor (see “Note 8 - Related parties”). The Company believes there are sufficient alternative vendors available to ensure a constant supply of cogeneration units on comparable terms. However, in the event of a change in suppliers, there could be a delay in obtaining units which could result in a temporary slowdown of installing additional income producing sites. In addition, the majority of the Company’s units are installed and maintained by the noncontrolling interest holder or maintained by Tecogen Inc., or Tecogen (see “Note 8 - Related parties”). The Company believes there are sufficient alternative vendors available to ensure a constant supply of maintenance and installation services on comparable terms. However, in the event of a change of vendor, there could be a delay in installation or maintenance services.
	Property, Plant and Equipment
	Property, plant and equipment are stated at cost. Depreciation and amortization are computed using the straight-line method at rates sufficient to write off the cost of the applicable assets over their estimated useful lives. Repairs and maintenance are expensed as incurred.
	The Company reviews the useful life of its energy systems on a quarterly basis or whenever events or changes in business circumstances indicate that the carrying value of the assets may not be fully recoverable or that the useful lives of the assets are no longer appropriate. The Company evaluates the recoverability of its long-lived assets when potential impairment is indicated by comparing the remaining net book value of the assets to the estimated future undiscounted cash flows attributable to such assets. The useful life of the Company’s energy systems is the lesser of the economic life of the asset or the term of the underlying contract with the customer, typically 12 to 15 years. If impairment is indicated, the asset is written down to its estimated fair value based on a discounted cash flow analysis. During 2014, the Company recorded asset impairment losses totaling $723,438 relating to certain of its energy systems as a result of changing or unexpected conditions with respect to the energy systems which impact the estimated future cash flows. The conditional changes impacting the estimated future cash flows related to these assets resulted from changes in the level of demand for electricity and/or hot water at particular installations, finalization of start-up period customization at particular installations and/or price changes in electrical and natural gas rates, all of which impacted estimated future cash flows.
	The Company receives rebates and incentives from various utility companies which are accounted for as a reduction in the book value of the assets. The rebates are payable from the utility to the Company and are applied against the cost of construction, therefore reducing the book value of the installation. As a reduction of the facility construction costs, these rebates are treated as an investing activity in the statements of cash flows. The rebates received by the Company from the utilities that apply to the cost of construction are one time rebates based on the installed cost, capacity and thermal efficiency of the installed unit and are earned upon the installation and inspection by the utility and are not related to or subject to adjustment based on the future operating performance of the installed units. The rebate agreements with utilities are based on standard terms and conditions, the most significant being customer eligibility and post-installation work verification by a specific date. During 2014 and 2013, the amount of rebates applied to the cost of construction was $27,500 and $285,718, respectively.
	Stock Based Compensation
	Stock based compensation cost is measured at the grant date based on the estimated fair value of the award and is recognized as an expense in the consolidated statements of operations over the requisite service period. The fair value of stock options granted is estimated using the Black-Scholes option pricing valuation model. The Company recognizes compensation on a straight-line basis over the expected life for each separately vesting portion of the option award. Use of a valuation model requires management to make certain assumptions with respect to selected model inputs. Expected volatility is calculated based on the Company’s historic volatility over the expected life of the option grant. The average expected life is estimated using the simplified method for “plain vanilla” options. The simplified method determines the expected life in years based on the vesting period and contractual terms as set forth when the award is made. The Company uses the simplified method for awards of stock-based compensation since it does not have the necessary historical exercise and forfeiture data to determine an expected life for stock options. The risk-free interest rate is based on U.S. Treasury zero-coupon issues with a remaining term which approximates the expected life assumed at the date of grant. When options are exercised the Company normally issues new shares.
	See “Note 5 – Stockholders’ equity” for a summary of the restricted stock and stock option activity under the Company’s stock-based employee compensation plan for the years ended December 31, 2014 and 2013, respectively.
	Loss per Common Share
	The Company computes basic loss per share by dividing net income (loss) for the period by the weighted average number of shares of common stock outstanding during the period. The Company computes diluted earnings per common share using the treasury stock method. For purposes of calculating diluted earnings per share, the Company considers its shares issuable in connection with convertible debentures, stock options and warrants to be dilutive common stock equivalents when the exercise price is less than the average market price of its common stock for the period. For the year ended December 31, 2014, the Company excluded 15,763,083 anti-dilutive shares resulting from exercise of stock options, warrants and shares issuable in connection with convertible debentures, and for the year ended December 31, 2013, the Company excluded 12,088,313 anti-dilutive shares resulting from exercise of stock options, warrants and unvested restricted stock. All shares issuable for both years were anti-dilutive because of the reported net loss.
	Income Taxes
	As part of the process of preparing its consolidated financial statements, the Company is required to estimate its income taxes in each of the jurisdictions in which it operates. This process involves the Company estimating its actual current tax exposure together with assessing temporary differences resulting from differing treatment of items, such as depreciation and certain accrued liabilities for tax and accounting purposes. These differences result in deferred tax assets and liabilities, which are included within the Company’s consolidated balance sheet. The Company must then assess the likelihood that its deferred tax assets will be recovered from future taxable income and to the extent it believes that recovery is not likely, the Company must establish a valuation allowance.
	The Company is allowed to recognize the tax benefits of uncertain tax positions only where the position is “more likely than not” to be sustained assuming examination by tax authorities. The amount recognized is the amount that represents the largest amount of tax benefit that is greater than 50.0% likely of being ultimately realized. A liability is recognized for any benefit claimed, or expected to be claimed, in a tax return in excess of the benefit recorded in the financial statements, along with any interest and penalties (if applicable) on that excess.
	The tax years 2003 through 2013 remain open to examination by major taxing jurisdictions to which the Company is subject, which are primarily in the United States, as carry forward attributes generated in years past may still be adjusted upon examination by the Internal Revenue Service or state tax authorities if they are or will be used in a future period. The Company is currently not under examination by the Internal Revenue Service or any other jurisdiction for any tax years. The Company did not recognize any interest and penalties associated with unrecognized tax benefits in the accompanying consolidated financial statements. The Company would record any such interest and penalties as a component of interest expense. The Company does not expect any material changes to the unrecognized benefits within twelve months of the reporting date.
	Fair Value of Financial Instruments
	The Company’s financial instruments are cash and cash equivalents, short-term investments, accounts receivable, accounts payable, convertible debentures and amounts due to/from related parties. The recorded values of cash and cash equivalents, accounts receivable, accounts payable and amounts due to/from related parties approximate their fair values based on their short-term nature. The warrant liability is recorded at fair value. The loan payable to related party is at fair value. The carrying value of the convertible debentures on the balance sheet at December 31, 2014 approximates fair value as the terms approximate those currently available for similar instruments. See “Note 9 - Fair value measurements.”
	Reclassifications
	In our 2013 Consolidated Balance Sheet, certain amounts between Convertible debentures and Convertible debentures due related parties have been reclassified to conform with current year presentation.
	New Accounting Pronouncements
	In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606),” to clarify the principles for recognizing revenue and to develop a common revenue standard for GAAP and the International Financial Reporting Standards. This guidance supersedes previously issued guidance on revenue recognition and gives a five step process an entity should follow so that the entity recognizes revenue that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This new guidance will be effective for our fiscal 2017 reporting period and must be applied either retrospectively during each prior reporting period presented or retrospectively with the cumulative effect of initially applying this guidance recognized at the date of the initial application. Early adoption is not permitted. We are currently evaluating the impact of the adoption of this ASU on our consolidated financial statements.
	In August 2014, the FASB issued ASU 2014-15 "Presentation of Financial Statements-Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern". The new standard provides guidance around management's responsibility to evaluate whether there is substantial doubt about an entity's ability to continue as a going concern and to provide related footnote disclosures. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016. Early adoption is permitted. The adoption of this ASU is not expected to have a material impact on our consolidated financial statements.

Property_plant_and_equipment

Property, plant and equipment	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, plant and equipment	Property, plant and equipment:
	Property, plant and equipment consist of the following as of December 31, 2014 and 2013, respectively:
		2014			2013
	Energy systems	$	31,185,095		$	25,567,808
	Computer equipment and software	132,543			122,853
	Furniture and fixtures	87,051			85,079
	Vehicles	226,018			243,139
		31,630,707			26,018,879
	Less — accumulated depreciation	(9,509,344		)	(7,621,242		)
		22,121,363			18,397,637
	Construction in progress	2,763,792			3,533,652
		$	24,885,155		$	21,931,289
	Depreciation expense of property, plant and equipment totaled $1,888,102 and $1,471,914 for the years ended December 31, 2014 and 2013, respectively.

Convertible_debentures

Convertible debentures	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Convertible debentures	Convertible debentures:
	American DG Energy Convertible Debentures
	On May 23, 2011, the Company issued $12,500,000 aggregate principal amount of debentures to John N. Hatsopoulos, the Company’s Co-Chief Executive Officer, and a principal owner of the Company. The debentures mature on May 25, 2018 and accrue interest at the rate of 6.0% per annum payable on a semi-annual basis. At the holder’s option, the debentures may be converted into shares of the Company’s common stock at a conversion price of $2.20 per share, subject to adjustment in certain circumstances. The Company has the option to redeem at 115% of Par Value any or all of the debentures after May 25, 2016. The debentures canceled the revolving line of credit agreement with John N. Hatsopoulos, which as of May 23, 2011 had a principal amount outstanding of $2,400,000.
	On November 30, 2011, the Company issued an additional $6,900,000 aggregate principal amount of debentures to the same principal owner of the Company. The debentures mature on May 25, 2018 and accrue interest at the rate of 6.0% per annum payable on a semi-annual basis. At the holder’s option, the debentures may be converted into shares of the Company’s common stock at a conversion price of $2.20 per share, subject to adjustment in certain circumstances. The Company has the option to redeem at 115% of Par Value any or all of the debentures after May 25, 2016.
	On January 10, 2013, at the request of all holders of the Company’s Senior Unsecured Convertible Debentures, due 2018, the Company modified through a third amendment the terms of the interest payment due to the holders. Under the terms of the third amendment, the holders agreed to receive interest payments on an annual basis starting on November 25, 2013 (instead of semi-annual interest payments) and that the Company use the average daily closing price of the Common Stock 10 business days before the interest payment due date in order to determine the conversion price. All other terms and conditions of the debentures, including interest rate and maturity date remained the same.
	On May 24, 2013, at the request of all holders of the Company’s Senior Unsecured Convertible Debentures, due 2018, the Company modified through a fourth amendment the terms of the interest payment due to the holders. Under the terms of the fourth amendment, the holders agreed to receive semi-annual interest payments on May 25th and November 25th in shares of the Company's common stock instead of cash for 2012, 2013 and 2014, provided that the Company's shares are listed on a National Securities Exchange. Under the terms of this amendment, for the May semi-annual interest payment, the Company will use the April average daily closing price of the Common Stock in order to determine the conversion price and for the November semi-annual interest payment the Company will use the October average daily closing price of the Common Stock in order to determine the conversion price. All other terms and conditions of the debentures, including interest rate and maturity date remained the same.
	On May 25, 2013, the total interest due to the debenture holders was $582,000 and in connection with the amendment the Company issued to the debenture holders 316,462 shares of common stock at $1.84 per share which was the average price of the Company's common stock during the month of April. In connection with this transaction, the Company recorded a reduction of $53,511 of non-cash interest expense, which was the difference between the average stock price and the fair market value on May 25, 2013.
	On July 2, 2013, the Company declared a special dividend of one share of EuroSite Power common stock for every ten shares of American DG Energy common stock (“special dividend”). The special dividend was paid on August 15, 2013, to stockholders of record as of the close of business on July 25, 2013. In connection with this transaction the Company, issued to its stockholders an aggregate of 4,880,679 shares of EuroSite Power common stock that it owns. Affiliates may sell the securities only after a 6 month holding period pursuant to the provisions of the SEC's Rule 144.
	On August 15, 2013, in connection with the special dividend, the Company modified the conversion price of the 6%, $19,400,000 debentures issued on May 23, 2011 and November 30, 2011 from $2.20 to $2.11 per share. The adjustment to the conversion price was not an automatic adjustment pursuant to the original terms of the debentures. Accordingly, the adjustment to the conversion price was accounted for as a modification under ASC 470. The modification of the convertible debt instrument resulted in an increase in the fair value of the embedded conversion option and the carrying amount of the debt instrument was reduced by approximately $649,000. This debt discount is being amortized over the remaining term of the debt. In accordance with ASC 820, the fair value of the conversion option at the date of modification was determined by utilizing a binomial lattice model with the following key assumptions:
	Company stock price	$1.64 per share
	Risk -free rate	1.43% - 1.45%
	Term	4.78 years
	Volatility	68.80%
	Dividend yield	—%
	On November 25, 2013, the total interest due to the debenture holders was $582,000 and in connection with the amendment the Company issued to the debenture holders 377,391 shares of common stock at $1.54 per share which was the average price of the Company's common stock during the month of October. In connection with this transaction, the Company recorded an additional charge of $59,562 of non-cash interest expense, which was the difference between the average stock price and the fair market value on November 25, 2013.
	On May 25, 2014, the total interest due to the debenture holders was $582,000 and the Company issued to the debenture holders 260,154 shares of common stock at $2.24 per share which was the average price of the Company's common stock during the month of April. In connection with this transaction, the Company recorded an additional charge of $42,368 of non-cash interest expense, which was the difference between the average stock price and the fair market value on May 25, 2014.
	On October 3, 2014, the Company consummated a series of transactions whereby, under an agreement with John N. Hatsopoulos and a principal owner of the Company whereby, the holders of the Company’s existing 6% Senior Unsecured Convertible Debentures Due 2018, paid the interest due under the convertible debentures through the next semiannual payment date of November 25, 2014 by delivering to the holders of the convertible debentures 1,164,000 shares of common stock of its subsidiary EuroSite Power, which were owned by the Company and which had a market value of $582,000. The Company also delivered 8,245,000 additional shares of EuroSite Power it owned with an aggregate market value of $4,122,500 to the holders of the convertible debentures for prepayment of all interest which would become due under the convertible debentures through the maturity date of May 25, 2018. In connection with these transactions, the Company delivered to the holders of the convertible debentures three-year warrants with an exercise price per share of $0.60 to purchase an additional 1,164,000 shares of EuroSite Power from the Company with an aggregate market value of $84,911.
	These transactions are reciprocal transfers and thus exchanges of non-monetary assets which are accounted for at fair value. The fair value recognized in recording the exchanges equaled the fair market value of the EuroSite Power shares relinquished and the amount of cash the counterparties to the exchange could have received in cash in lieu of accepting the shares, which amounts were identical with the exception of the additional value ascribed to the warrants of $84,911. No gain or loss was recognized relative to these transactions under ASC 810-10-45-23 since the Company retained a controlling financial interest in EuroSite Power following these transactions. Accordingly, these transactions were accounted for as equity transactions with any difference between the fair value assigned and the necessary adjustment to noncontrolling interest being assigned to the additional paid-in capital of the Company.
	Following the payment of all current and future interest under the convertible debentures, the Company exchanged the convertible debentures which bore interest at an annual rate of 6% for non-interest bearing convertible debentures, the 2014 Convertible Debentures, with all other terms including the principal amount, maturity date, and conversion terms and privileges remaining unchanged.
	The exchange of debentures was not considered to be an extinguishment under ASC 470-50 as the debt instruments exchanged were not considered to have substantially different terms and, accordingly, no gain or loss was recognized. The existing basis in the convertible debentures prior to the exchange was carried over and an additional discount equal to the fair value of the EuroSite Power shares exchanged for future interest and the fair value of the warrants was recorded. The total discount, including the fair value of the warrant of $84,911, was $4,207,411. The revised discount is being amortized to interest expense on the interest method. The effective interest rates to fully accrete the 2014 Convertible Debentures to their face value at maturity is 7.8%.
	The unamortized discount at December 31, 2014 was $4,523,051 and non-cash interest expense related to amortization of the discount in the year ended December 31, 2014 was $162,486.
	Eurosite Power Convertible Debentures
	On February 26, 2013, EuroSite Power issued a promissory note in the amount of $1,100,000 to the Company. Under the terms of the agreement EuroSite Power was to pay interest at a rate of 6.0% per annum payable quarterly in arrears.
	On June 14, 2013, EuroSite Power entered into subscription agreements with certain investors, including the Company, for a private placement of an aggregate principal amount of $4,000,000 of 4% Senior Unsecured Convertible Notes Due 2015, or the Notes. In connection with the private placement, the Company exchanged the promissory note in the aggregate principal amount of $1,100,000, originally issued on February 26, 2013 for a like principal amount of the Notes and cash paid for any accrued but unpaid interest. Included among the investors subscribing for the Notes are: Bruno Meier, a director of EuroSite, in the amount of $250,000; Joan Giacinti, a director of the Company and EuroSite Power, in the amount of $300,000; Charles T. Maxwell, Chairman of the Board of Directors of the Company, in the amount of $250,000; Nettlestone Enterprises Limited, a shareholder of both Eurosite Power and the Company, in the amount of $300,000; Perastra Management S.A., an investor in the Company and EuroSite Power, in the amount of $1,500,000; and Yves Micheli, an investor in EuroSite Power, in the amount of $300,000. The proceeds of the offering of the Notes will be used in connection with the development and installation of current and new energy systems, business development and for general corporate purposes.
	The holders of the Notes are subject to and entitled to the benefits of the 4% Senior Convertible Notes due 2015 Noteholders Agreement, dated June 14, 2013, or the Noteholders Agreement. The Notes will mature on June 14, 2015 and will accrue interest at the rate of 4% per annum payable in cash on a semi-annual basis. At the Investor's option, the Notes may be converted into shares of EuroSite Power's common stock at an initial conversion rate of 1,000 shares of common stock per $1,000 principal amount of Notes, subject to adjustment. At the scheduled maturity date, each of the Investors will have the following options: request payment of their principal amount and accrued interest in cash; extend the term of the Notes for an additional 3 years with an automatic decrease in interest rate to 3% per annum; or exchange the Notes for a new non-convertible note with a 3 year maturity and a 6% per annum interest rate; no accrued interest will be lost on such exchange.
	EuroSite Power initially concluded that the term-extending option mentioned above was an embedded derivative with de minimis value but has subsequently concluded that it is not considered a derivative under ASC 815-Derivatives and Hedging because the term extending feature is considered clearly and closely related to the Notes. Thus, this feature was no required to be bifurcated and no other initial accounting was required. The term-extending option has subsequently been eliminated pursuant to the note exchange agreements discussed below.
	The Noteholders Agreement provides for customary events of default by EuroSite Power, including failure to pay interest within ten days of becoming due, failure to pay principal when due, failure to comply provisions of the Notes or the Noteholders Agreement, subject to cure, and certain events of bankruptcy or insolvency.
	The holders of the Notes are entitled to the benefits of a registration rights agreement dated June 14, 2013 by and among EuroSite Power and the Noteholders named therein, or the Registration Rights Agreement. The Registration Rights Agreement provides for demand registration rights, such that upon the demand of 30% of the holders of Registrable Securities, as defined in the Registration Rights Agreement and subject to certain conditions (including that EuroSite Power is eligible to use a Form S-3 registration statement and that such holders anticipate an aggregate offering price, net of selling expenses, of at least $250,000), EuroSite Power will file a Form S-3 registration statement covering the Registrable Securities requested to be included in such registration, subject to adjustment.
	On February 20, 2014, EuroSite Power accepted certain separate note exchange agreements, or the Note Exchange Agreements, from the holders of the Notes, pursuant to which EuroSite Power exchanged the Notes for like principal amounts of 4% Senior Convertible Notes Due 2017, or the New Notes, in an aggregate principal amount of $4,000,000. Accrued but unpaid interest on the Notes was treated as accrued interest under the New Notes. Included among the investors exchanging their Notes for New Notes were: the Company, in the amount of $1,100,000; Bruno Meier, a director of EuroSite Power, in the amount of $250,000; Prime World Inc., a company controlled by Joan Giacinti, one of the Company's directors, in the amount of $300,000; Charles T. Maxwell, Chairman of the Board of Directors of the Company, in the amount of $250,000; Nettlestone Enterprises Limited, a shareholder of both EuroSite Power and the Company, in the amount of $300,000; Perastra Management S.A., an investor in the Company and EuroSite Power, in the amount of $1,500,000; and Yves Micheli, an investor in EuroSite Power, in the amount of $300,000.
	The effect of the Note Exchange agreement (a) extended the maturity date from June 14, 2015 to June 14, 2017, (b) adjusted the conversion price of the notes which changed from 1,000 shares of EuroSite Power's common stock for each $1,000 of principal converted to 1,667 shares of EuroSite Power’s common stock for each $1,000 of principal converted, and (c) eliminated the Holders’ options to extend the Notes. The Company analyzed the impact of the Note Exchange Agreement and determined that the Notes and the New Notes were substantially different and, as a result, EuroSite Power recognized a loss on extinguishment of $713,577 to recognize the excess of the fair value of the New Notes that were issued in the exchange over the carrying value of the Notes surrendered, of which, $180,400 related to the Company's holdings and was eliminated in consolidation. The New Notes were recorded at fair value as of the date of the exchange with the difference between the fair value of the debt of $4,656,000 and the carrying value of $4,000,000, or $656,000, being recorded as a premium. The portion of the $656,000 premium attributable to the Company's holdings, or $180,400, is eliminated in consolidation. The interest method of accounting is used to amortize the premium over the life of the New Notes. The fair value of the New Notes was determined using a binomial lattice model.  The following table provides quantitative information used in the fair value measurement, including the assumptions for the significant unobservable inputs used in the binomial lattice model valuation:
	Notional amount	$	4,000,000
	Par amount	$	1,000
	Interest rate	4
	Conversion ratio	1,667
	Conversion price, per share	$	0.6
	Stock price as of the valuation date	$	0.51
	Historical realized weekly volatility	87			%
	Risk free rate	0.9			%
	Discrete dividend payment rate	—			%
	Significant increases (decreases) in the significant unobservable inputs used in the fair value measurement of the New Notes would result in a significantly higher (lower) fair value measurement.
	Effective April 15, 2014 and April 24, 2014 EuroSite Power, entered into a subscription agreements with John N. Hatsopoulos, the chairman of the Company's Board of Directors, certain other investors and a principal owner of the Company for the sale of a $1,450,000, 4% Senior Convertible Note Due 2018. The 2014 Notes will mature in four years and will accrue interest at the rate of 4% per annum payable on a semi-annual basis. At the holder’s option, the 2014 Notes may be converted into shares of the EuroSite Power’s common stock at a conversion price of $0.60 per share, subject to adjustment in certain circumstances. The proceeds of the 2014 Notes will be used in connection with the development and installation of current and new energy systems, business development and for general corporate purposes.
	On October 3, 2014, EuroSite Power, entered into convertible note amendment agreements, or the Note Amendment Agreements, with the Company, John N. Hatsopoulos and principal owner of the Company, as well as certain separate convertible note conversion agreements, or the Note Conversion Agreements, with certain other investors, which eliminated $3,050,000 of EuroSite Power's convertible notes.
	Among other things, the Note Amendment Agreements provided for the conversion, in full, of the principal amount of certain of the Notes and the 2014 Notes or collectively, the Converted Notes, in an aggregate principal amount of $3,050,000, pursuant to which the holders of such Converted Notes, or the Holders, agreed to convert, in full, the principal amount of the Converted Notes. In connection with the conversion, the Converted Notes were cancelled and the Holders were issued 6,100,000 shares of EuroSite Power’s common stock at a conversion price of $.50 per share, with any accrued but unpaid interest to be paid in cash.
	The conversion price of $.50 per share was less than the $.60 per share that was contractually provided for on the convertible debentures. Accordingly, in accordance with ASC 470-20-40, this transaction was accounted for as an inducement conversion with the fair value of the incremental shares issued being recognized as an expense. On a consolidated basis after elimination of intercompany items, the expense recognized was $324,977.
	The unamortized premium was $232,710 at December 31, 2014 and non-cash interest income related to amortization of the premium for the year-ended December 31, 2014 was $127,554, which was net with interest expense.
	The Company guarantees (the “Guarantees”), the remaining Notes on a subordinated basis. Among other things, the Guarantees provide that, in the event of EuroSite Power's failure to pay principal or interest on a Note, the holder of such Note, on the terms and conditions set forth in the Notes, may proceed directly against the Company, as guarantor, to enforce the Guarantee. These securities were offered and sold to the investors in private placement transactions made in reliance upon exemptions from registration pursuant to Section 4(a)(2) under the Securities Act of 1933 and Rule 506 promulgated thereunder. The investors are accredited investors as defined in Rule 501 of Regulation D promulgated under the Securities Act of 1933.
	The face amount of convertible debentures and the related premium or discount are as follows as of December 31, 2014 and 2013, respectively:
		2014
		American DG Energy			EuroSite Power			Total
	Face amount	$	19,400,000		$	2,400,000		$	21,800,000
	Premium (discount)	(4,523,051		)	232,710			(4,290,341		)
		14,876,949			2,632,710			17,509,659
	Less amounts due to related parties	(14,876,949		)	(987,266		)	(15,864,215		)
		$	—		$	1,645,444		$	1,645,444
		2013
		American DG Energy			EuroSite Power			Total
	Face amount	$	19,400,000		$	4,000,000		$	23,400,000
	Premium (discount)	(601,620		)	—			(601,620		)
	Elimination	—			(1,100,000		)	(1,100,000		)
		18,798,380			2,900,000			21,698,380
	Less amounts due to related parties	(18,798,380		)	(1,100,000		)	(19,898,380		)
		$	—		$	1,800,000		$	1,800,000
	Certain December 31, 2013 related party convertible debenture balances have been reclassified to conform with current period presentation.

Stockholders_equity

Stockholders' equity	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Stockholders' equity	Stockholders’ equity:
	Common Stock
	On August 28, 2013, after the closing of trading on the NYSE-MKT, the Company, entered into a subscription agreement with Charles T. Maxwell, the Company's Chairman of the Board, or the Investor, selling to the Charles T. Maxwell IRA an aggregate of 300,000 shares of the Company's Common Stock, $.001 par value per share, or the Securities, at a purchase price of $1.55 per share for an aggregate purchase price of $465,000. Under this agreement, the Company was required at its own cost to file with the SEC a registration statement covering the resale of such shares. The proceeds of this private placement will be used to fund additional installations of the Company's On-Site Utility energy systems and for general corporate and working capital purposes. The Securities were offered and sold to the Investor in a private placement transaction made in reliance upon an exemption from registration pursuant to Section 4(a)(2) under the Securities Act of 1933, as amended, or the Securities Act. The Investor is an accredited investor as defined in Rule 501 of Regulation D promulgated under the Securities Act.
	On September 4, 2013, after the closing of trading on the NYSE-MKT, the Company, entered into a subscription agreement with Frost Gamma Investments Trust, or the Trust, an accredited investor, by selling to the Trust an aggregate of 333,334 shares of the Company's common stock at a per share price of $1.50 for an aggregate purchase price of $500,001. Under this agreement, the Company was required at its own cost to file with the SEC a registration statement covering the resale of such shares. The proceeds of this private placement will be used to fund additional installations of the Company's On-Site Utility energy systems and for general corporate and working capital purposes. The Securities were offered and sold to the Investor in a private placement transaction made in reliance upon an exemption from registration pursuant to Section 4(a)(2) under the Securities Act of 1933, as amended, or the Securities Act. The Investor is an accredited investor as defined in Rule 501 of Regulation D promulgated under the Securities Act.
	On August 6, 2014, the Company entered into an underwritten offering with an underwriter whereby the Company issued: (i) 2,650,000 shares of its common stock, (ii) three-year warrants to purchase up to 2,829,732 shares of its common stock and five-year warrants to purchase an additional 112,538 to the underwriters with an exercise price of $1.89 per share and net proceeds of $3,269,275.
	The Company continues to use the net proceeds of the offering for working capital purposes in connection with development and installation of current and new energy systems.
	The holders of common stock have the right to vote their interest on a per share basis. At December 31, 2014, there were 52,140,001 shares of common stock outstanding.
	Warrants
	Other than as noted in Common Stock above, the Company issued no warrants in the year ended December 31, 2014.
	Warrant activity for the years ended December 31, 2014 and 2013 was as follows:
		Number of			Weighted Average
		Warrants			Exercise Price
	Balance, December 31, 2012	565,500			$	3.19
	Granted	—			—
	Exercised	—			—
	Expired	(58,000	)		3
	Balance, December 31, 2013	507,500			$	3.24
	Granted	2,942,270			1.89
	Exercised	—			—
	Expired	—			—
	Balance, December 31, 2014	3,449,770			$	2.09
	Stock Based Compensation – American DG Energy
	The Company has adopted the 2005 Stock Incentive Plan, or the Plan, under which the board of directors may grant incentive or non-qualified stock options and stock grants to key employees, directors, advisors and consultants of the Company.
	The maximum number of shares of stock allowable for issuance under the Amended Plan is 8,000,000 shares of common stock. Stock options vest based upon the terms within the individual option grants, usually over a two- or ten-year period with an acceleration of the unvested portion of such options upon a liquidity event, as defined in the Company’s stock option agreement. The options are not transferable except by will or domestic relations order. The option price per share under the Amended Plan is not less than the fair market value of the shares on the date of the grant.
	During the years ended December 31, 2014 and 2013, the Company recognized employee non-cash compensation expense of $310,900 and $315,245, respectively. At December 31, 2014, the total compensation cost related to unvested stock option awards not yet recognized is $696,870. This amount will be recognized over the weighted average period of 1.0 year.
	In 2013, the Company granted 80,000 nonqualified options to purchase shares of its common stock to a director and 350,000 to two employees at prices ranging between $1.54 and $1.67 per share. Those options have a vesting schedule 4 years and 280,000 of them expire in 10 years while 150,000 expire in 5 years. The fair value of all options issued in 2013 was $368,044, with a weighted average grant date fair value of $0.86 per option.
	The weighted average assumptions used in the Black-Scholes option pricing model are as follows:
		2014			2013
	Stock options and restricted stock awards
	Expected life	6.25 years			5 years
	Risk-free interest rate	2.03	%		1.75	%
	Expected volatility	68.8	%		60.3	%
	Stock option activity for the years ended December 31, 2014 and 2013 was as follows:
	Common Stock Options	Number of Options		Weighted Average Exercise Price			Weighted Average Remaining Life	Aggregate Intrinsic Value
	Outstanding, December 31, 2013	2,386,500		$	1.49		4.13 years	$	1,092,550
	Granted	1,069,000		1
	Exercised	—		—
	Canceled	(286,500	)	1.72
	Expired	(50,000	)	0.7
	Outstanding, December 31, 2014	3,119,000		$	1.32		5.15 years	$	25,600
	Exercisable, December 31, 2014	1,360,250		$	1.5			$	—
	Vested and expected to vest, December 31, 2014	3,119,000		$	1.32			$	25,600
	For year-ended December 31, 2014, the fair value of all options granted was $678,570 and the weighted average grant date fair value was $0.63. For year-ended 2013, the fair value of the 430,000 options granted was $368,044 and the weighted average grant date fair value was $0.86. The aggregate intrinsic value of options outstanding as of December 31, 2014 is calculated as the difference between the exercise price of the underlying options and the price of the Company’s common stock for options that were in-the-money as of that date. Options that were not in-the-money as of that date, and therefore have a negative intrinsic value, have been excluded from this amount.
	Stock-Based Compensation – EuroSite Power
	In January 2011, EuroSite Power adopted the 2011 Stock Incentive Plan, or the Plan, under which their board of directors may grant up to 3,000,000 shares of incentive or non-qualified stock options and stock grants to key employees, directors, advisors and consultants of EuroSite Power. On June 13, 2011, their board of directors unanimously amended the Plan to increase the reserved shares of common stock issuable under the Plan from 3,000,000 to 4,500,000, or the Amended Plan.
	Stock options vest based upon the terms within the individual option grants, usually over a four year period with an acceleration of the unvested portion of such options upon a liquidity event, as defined in EuroSite Power’s stock option agreement. The options are not transferable except by will or domestic relations order. The option price per share under the Amended Plan is not less than the fair value of the shares on the date of the grant. The number of securities remaining available for future issuance under the Amended Plan was 195,000 at December 31, 2014.
	On March 20, 2013, EuroSite Power granted to a director options to purchase 100,000 shares of common stock, to a consultant options to purchase 50,000 shares of common stock, and to six employees options to purchase 88,000 shares of common stock. Those options have a vesting schedule of 4 years and expire in 10 years.
	On October 15, 2013, EuroSite Power granted to an Officer 200,000 options to purchase shares of common stock. Those options having a vesting schedule of 4 years and expire in 10 years.
	At December 31, 2014, EuroSite Power had 4,305,000 options outstanding and recognized employee non-cash compensation expense of $164,999 related to the issuance of those stock options. For the year ended December 31, 2014 the total compensation cost related to unvested stock option awards not yet recognized was $139,559. This amount will be recognized over the weighted average period of 1.61 years.
	Stock option activity for the year ended December 31, 2014 was as follows:
	Common Stock Options	Number of Options		Weighted Average Exercise Price			Weighted Average Remaining Life		Aggregate Intrinsic Value
	Outstanding, December 31, 2013	4,025,000		$	0.87		7.58 years		$	74,000
	Granted	520,000		0.65
	Exercised	—		—
	Canceled	(240,000	)	0.49
	Expired	—		—			—		—
	Outstanding, December 31, 2014	4,305,000		$	0.87		6.84 years		$	9,800
	Exercisable, December 31, 2014	2,721,250		$	0.9				$	—
	Vested and expected to vest, December 31, 2014	4,305,000		$	0.87				$	9,800
	The aggregate intrinsic value of options outstanding as of December 31, 2014 is calculated as the difference between the exercise price of the underlying options and the price of EuroSite Power’s common stock for options that were in-the-money as of that date. Options that were not in-the-money as of that date, and therefore have a negative intrinsic value, have been excluded from this amount.
	During the years ended December 31, 2014 and 2013, the consolidated Company recognized employee non-cash compensation expense of $475,899 and $596,349, respectively, related to the issuance of stock options by the Company and EuroSite Power. At December 31, 2014 and December 31, 2013, the total compensation cost related to unvested stock option awards, for the Company, including EuroSite Power, not yet recognized was $836,429 and $740,221, respectively.
	The following schedule discloses the effects of changes in the Company's ownership interest in its subsidiary EuroSite Power on the Company's equity for the year ended December 31, 2014:
	Net loss attributable to American DG Energy Inc.		$	(5,888,894	)
	Transfers (to) from noncontrolling interest:
Increase in American DG Energy Inc.'s additional paid-in capital for exchange of 9,409,000 EuroSite Power common shares for current and future interest related to the Company's convertible debentures (see "Note 4 Convertible debentures")		4,704,500
Increase in American DG Energy Inc.'s additional paid-in-capital for sale by EuroSite Power of 3,000,000 common shares and warrants		1,486,329
Decrease in American DG Energy Inc.'s additional paid-in-capital for reacquisition by EuroSite Power of 100,000 of its common shares		(42,902		)
Increase in American DG Energy Inc.'s additional paid-in-capital for conversion of EuroSite Power convertible debentures into 6,100,000 common shares of EuroSite Power		2,455,377
Noncontrolling interest share of transactions affecting subsidiary ownership		(2,718,159		)
Subtotal transfers (to) from noncontrolling interest		5,885,145
Change from net loss attributable to American DG Energy Inc. and transfers (to) from noncontrolling interest		$	(3,749	)

Warrant_liability

Warrant liability	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Warrant liability	Warrant liability:
	In connection with a subscription agreement that the Company entered into on December 9, 2010, the Company issued warrants for the purchase of 500,000 shares of its common stock. The warrants have an exercise price of $3.25 and are exercisable for five years, commencing six months after the closing of the offering and expire on December 14, 2015.
	The warrants contain both a right to obtain stock upon exercise, or a Call, and a right to settle the warrants for cash upon the occurrence of certain events, or a Put. Generally, the Put provisions allow the warrant holders liquidity protection; the right to receive cash equal to the value of the remaining unexercised portion of the warrants in certain situations where the holders would not have a means of readily selling the shares issuable upon exercise of the warrants (e.g., where there would no longer be a significant public market for the Company’s common stock). Specifically, the Put rights would be triggered upon the occurrence of a Fundamental Transaction as defined in the agreement. Pursuant to the agreement, in the case of a Fundamental Transaction the warrant holders would receive a cash settlement in an amount equal to the value of obtained by using the Black Scholes Option Pricing Model obtained from the “OV” function on Bloomberg L.P. using (i) a price per share of Common Stock equal to the Volume-Weighted Average Price of the Common Stock for the Trading Day immediately preceding the date of consummation of the applicable Fundamental Transaction, (ii) a risk-free interest rate corresponding to the U.S. Treasury rate for a period equal to the remaining term of this Warrant as of the date of consummation of the applicable Fundamental Transaction and (iii) an expected volatility equal to the lesser of (1) the thirty (30) day volatility obtained from the “HVT” function on Bloomberg L.P. determined as of the end of the Trading Day immediately following the public announcement of the applicable Fundamental Transaction or (2) 70%. These warrants are classified as liabilities pursuant to the FASB guidance contained in ASC 480. Changes in the fair value of the warrant liabilities are recorded in the accompanying statements of operations (see “Note 9 – Fair value measurements”).

Employee_benefit_plan

Employee benefit plan	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Employee benefit plan	Employee benefit plan:
	The Company has a defined contribution retirement plan, or the Retirement Plan, which qualifies under Section 401(k) of the Internal Revenue Code, or the IRC. Under the Retirement Plan, employees meeting certain requirements may elect to contribute a percentage of their salary up to the maximum allowed by the IRC. The Company matches a variable amount based on participant contributions up to a maximum of 4.50% of each participant’s salary. The Company contributed $49,816 and $53,697 to the Retirement Plan for the years ended December 31, 2014 and 2013, respectively.

Related_parties

Related parties	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related parties	Related parties:
	Eurosite Power, Tecogen, Ilios Inc., or Ilios are affiliated companies by virtue of common ownership.
	The Company purchases the majority of its cogeneration units from Tecogen, an affiliate Company sharing similar ownership. In addition, Tecogen pays certain operating expenses, including benefits and payroll, on behalf of the Company and the Company leases office space from Tecogen. These costs were reimbursed by the Company. For year-ending December 31, 2014 and 2013, the Company bought equipment and maintenance services form Tecogen of $1,432,801 and $817,700, respectively.
	In July 2012, the Company entered into a Facilities, Support Services and Business Agreement, or the Agreement, with Tecogen, to provide the Company with certain office and business support services for a period of one year, renewable annually by mutual agreement. Under the current amendment to the Agreement, Tecogen provides the Company with office space and utilities at a monthly rate of $6,495. On July 1, 2013 and November 12, 2013, the Company entered into an Amendments with Tecogen. The Amendments renews the term of the Facilities, Support Services and Business Agreement between the Company and Tecogen. The Amendments further clarifies that the total sales thresholds for volume discounts are to be met during a calendar year and that the Company's representation rights may be terminated by either the Company or Tecogen upon 60 days' notice, without cause. The Amendments state that in New England States the Company shall have the right to purchase Cogeneration products directly from Tecogen as described in the agreement so long as the Company intended use is it to retain long-term ownership of the Cogeneration product and utilize it for the production and sale of electricity and thermal energy. Tecogen will not sell its products to parties for which the intended use is to earn revenue from metered energy to third parties (i.e., ADG Energy “On-Site Utility” energy projects) other than the Company. In cases where the Company has the opportunity to sell Cogeneration products to an unaffiliated party in the New England States and where Tecogen has no other appointed representation in that specific region, the Company may buy/resell the Cogeneration product as specified under the terms of this agreement. If, however, Tecogen has appointed a local exclusive representative in that specific New England region, The Company will defer to the local representative for pricing and other specific details for working cooperatively. The Company has granted Tecogen sales representation rights on its On-Site Utility energy service in California.
	In March 2013 the Company provided Tecogen, a related party, funds as prepayment for equipment purchases and services to be delivered or performed in 2013. The Company received a 6.0% per annum discount on deposit balances towards future purchases.
	On October 22, 2009, the Company signed a five-year exclusive distribution agreement with Ilios Inc., or Ilios, a subsidiary of Tecogen. Under terms of the agreement, the Company has exclusive rights to incorporate Ilios’ ultra-high-efficiency heating products, such as a high efficiency water heater, in its energy systems throughout the European Union and New England. The Company also has non-exclusive rights to distribute Ilios’ product in the remaining parts of the United States and the world in cases where the Company retains ownership of the equipment for its On-Site Utility business.
	On November 12, 2013, the Company entered into the First Amendment to the Sales Representative Agreement with Ilios. The Amendment allows Ilios to appoint sales representatives in the European Union (EU) in addition to the Company. For nations of the EU the company has the right under this agreement to purchase Ilios products directly from Ilios at a stipulated price so long as the Company intends use is to retain long-term ownership of the Ilios product and utilize it for the production and sale of thermal energy (i.e., ADG Energy/EuroSite Power “On-Site Utility” energy projects). Ilios will not sell its products to parties for which the intended use is to earn revenue from metered energy to third parties (i.e., ADG Energy/EuroSite Power “On-Site Utility” energy projects) other than the Company. In cases where the Company has the opportunity to sell Ilios product to an unaffiliated party in the EU and where Ilios has no other appointed representation in that specific region, the Company may buy/resell the Ilios product as specified under the terms of this contact. If, however, Ilios has appointed a local exclusive representative in that specific EU region, the Company will defer to the local representative for pricing and other specific details for working cooperatively.
	On September 19, 2014, John Hatsopoulos loaned EuroSite Power $3,000,000 without interest pursuant to a promissory note (the "Loan"). The Loan matures upon a substantial capital raise or on September 19, 2019. Prepayment of principal may be made at any time without penalty. The proceeds of the Loan will be used in connection with the development and installation of current and new energy systems in the United Kingdom and Europe. On December 30, 2014, the EuroSite Power amended and restated the existing promissory note to provide for interest at a rate of 1.85%.
	For a description of related party transactions see Note 4 "Convertible debentures".

Fair_value_measurements

Fair value measurements	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair value measurements	Fair value measurements:
	The fair value topic of the FASB Accounting Standards Codification defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The accounting guidance also establishes a fair value hierarchy which requires an entity to maximize the use of observable inputs, where available, and minimize the use of unobservable inputs when measuring fair value. There are three levels of inputs that may be used to measure fair value:
	Level 1 — Unadjusted quoted prices in active markets for identical assets or liabilities. The Company currently does not have any Level 1 financial assets or liabilities.
	Level 2 — Observable inputs other than quoted prices included in Level 1. Level 2 inputs include quoted prices for identical assets or liabilities in non-active markets, quoted prices for similar assets or liabilities in active markets and inputs other than quoted prices that are observable for substantially the full term of the asset or liability. The Company considers its convertible debentures a level 2 liability and believes that its carrying value approximates fair value.
	Level 3 — Unobservable inputs reflecting management’s own assumptions about the input used in pricing the asset or liability.
	As of December 31, 2014, the Company has classified the warrants with put and call rights as Level 3 (see “Note 6 – Warrant liability”). The Company estimated that the fair value of the warrants using a Black-Scholes option pricing model under various probability-weighted outcomes which take into consideration the protective, but limited, cash-settlement feature of the warrants. At issuance, the following average assumptions were assigned to the varying outcomes: expected volatility of 57.0%, risk free interest rate of 2.08%, expected life of five years and no dividends. The Company estimated that the fair value of the warrants at December 31, 2014 using this same model with the following average assumptions assigned to the varying outcomes: expected volatility of 91.4%, risk free interest rates of 0.02%, expected lives of 0.96 and no dividends. As of December 31, 2014, the financial liabilities held by the Company and measured at fair value on a recurring basis (which consist solely of the warrant liability) were $6,780. The following table summarizes the warrant activity for the period:
		Warrant Liabilities
	Fair value at December 31, 2013	$	132,265
	Fair value adjustment at December 31, 2014	(125,485		)
	Fair value at December 31, 2014	$	6,780
	In connection with the Company’s asset impairment analysis (See “Note 2 - Summary of significant accounting policies” - Property, plant and equipment),  the Company utilized Level 3 category fair value measurements. Those measurements employed the use of discounted cash flow analysis to determine the fair value of certain energy systems. These analyses considered any conditional change which may impact the estimated future cash flows related to these assets resulting from changes in the level of demand for electricity and/or hot water at particular installations, finalization of start-up period customization at particular installations and/or price changes in electrical and natural gas rates, all of which impacted estimated future cash flows. The estimated expected cash flows were than discounted at a rate of 6% per annum.

Income_taxes

Income taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income taxes	Income taxes:
	Reconciliation of federal statutory income tax provision to the Company’s actual provision for the years ended December 31, 2014 and 2013, respectively, are as follows:
		2014			2013
	Benefit at federal statutory tax rate	$	(2,222,000	)	$	(1,647,000	)
	Foreign rate differential	159,000			141,330
	UK Energy Incentives	(649,000		)	—
	Unbenefited operating losses	2,062,960			1,505,670
	Provision for income taxes	4,000			13,450
	Income tax provision	$	(645,040	)	$	13,450
	The component of net deferred tax assets recognized in the accompanying balance sheets at December 31, 2014 and 2013, respectively, are as follows:
		2014			2013
	Net operating loss carryforwards	$	10,838,000		$	9,902,000
	Accrued expenses and other	100,000			200,000
	Stock compensation	1,194,000			1,014,000
	Depreciation	(216,000		)	(516,000		)
		11,916,000			10,600,000
	Valuation allowance	(11,916,000		)	(10,600,000		)
	Net deferred tax asset	$	—		$	—
	As of December 31, 2014, the Company has federal and state loss carryforwards of approximately $24,683,000 and $19,865,000, respectively, which may be used to offset future federal and state taxable income, expiring at various dates through 2034. Included in these net operating losses is $1,353,000 of excess stock compensation deductions, related to the amount of tax deductions on restricted stock, in excess of book compensation expense. As of December 31, 2014, the Company also has foreign loss carryforwards of approximately $3,595,000 which may be used to offset future foreign taxable income. Management has determined that it is more likely than not that the Company will not recognize the benefits of the federal and state deferred tax assets and as a result has recorded a valuation allowance against the entire net deferred tax asset. If the Company should generate sustained future taxable income, against which these tax attributes may be recognized, some portion or all of the valuation allowance would be reversed. The valuation allowance increased by $1,316,000 during the year-ended December 31, 2014, due primarily to net operating losses generated, stock compensation and depreciation. The valuation allowance increased $1,511,000 during year-ended December 31, 2013, due primarily to net operating losses generated, stock compensation and depreciation.
	The tax years 2003 through 2013 remain open to examination by major taxing jurisdictions to which the Company is subject, which are primarily in the United States, as carry forward attributes generated in years past may still be adjusted upon examination by the Internal Revenue Service or state tax authorities if they are or will be used in a future period. The Company is currently not under examination by the Internal Revenue Service or any other jurisdiction for any tax years. The Company did not recognize any interest and penalties associated with unrecognized tax benefits in the accompanying consolidated financial statements.
	The Company has no uncertain tax positions as of December 31, 2014.
	In 2014, the Company recognized an United Kingdom energy tax incentive benefit of $649,000 for "Advanced Capital Allowances" (ECA), whereby the Company will receive a cash benefit that is an acceleration of tax relief on capital expenditures of co-generation equipment put into service at approved sites in the UK.
	The Company's federal and state net operating losses could be limited to the extent that there are significant changes in ownership of the Company's stock. The company has not assessed the impacts of these limitations on its tax attributes.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	Commitments and contingencies:
	On July 1, 2013 the Company entered into an Amendment to the Facilities, Support Services and Business Agreement, or the Amendment, with Tecogen. The Amendment renews the term of the Facilities, Support Services and Business Agreement between the Company and Tecogen for a one year period, beginning on July 1, 2013. The Amendment also increases the space provided to the Company by Tecogen from approximately 3,071 square feet to 3,282 square feet and from six offices to nine offices. Under the Amendment, the amount that the Company will pay Tecogen for the space and services that Tecogen provides under the Agreement increased to $6,495 per month.
	On November 12, 2013, the Company entered into the Second Amendment to the Facilities, Support Services and Business Agreement, or the Second Amendment. The Second Amendment extended the lease and allowed year-to-year renewals.

Subsequent_events

Subsequent events	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent events	Subsequent events:
	On January 28, 2015, on the recommendation of the Chairman of the Board of the Company, the Board of Directors appointed Dr. Elias Samaras as a member of the Company’s Board of Directors. Dr. Samaras shall hold such position until the next annual meeting of the stockholders of the Company or until his successor shall have been duly elected and qualified.
	On January 29, 2015, the Company, entered into an exchange agreement, or the Exchange Agreement, with IN Holdings Corp., a holder of more than five percent of the Company’s common stock, or IN Holdings. In part, the Exchange Agreement provided that IN Holdings agreed to transfer to the Company 1,320,000 shares of the Company’s common stock, and that in exchange, the Company agreed to transfer to IN Holdings 1,320,000 shares of the common stock of EuroSite Power Inc.
	On February 6, 2015, Barry Sanders resigned from his positions as President and Chief Operating Officer of the Company, and any other positions he may have had with the Company and the Company’s affiliates, including the Company’s majority owned subsidiary EuroSite Power Inc. Mr. Sanders will continue to serve as a consultant to the Company.
	The Company has evaluated subsequent events through the date of this filing and determined that no other subsequent events occurred that would require recognition in the consolidated financial statements or disclosure in the notes thereto.

Summary_of_significant_account1

Summary of significant accounting policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Principles of Consolidation and Basis of Presentation	The accompanying consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) and include the accounts of the Company and entities in which it has a controlling financial interest. Those entities include the Company's 51.0% joint venture, American DG New York, LLC, or ADGNY, and its 50.1% owned subsidiary EuroSite Power Inc., or EuroSite Power. The interests in underlying energy system projects in the joint venture vary between the Company and its joint venture partner. As the controlling partner, all major decisions in ADGNY are made by the Company according to the joint venture agreement. Distributions, however, are made based on the economic ownership. The economic ownership is calculated by the amount invested by the Company and the noncontrolling partner in each site. Each quarter the Company calculates a year-to-date profit/loss for each site that is part of ADGNY and the noncontrolling interest percent ownership in each site is applied to determine the noncontrolling interest share in the profit/loss. The Company follows the same calculation regarding available cash and a cash distribution is made to the noncontrolling interest partner each quarter. On the Company’s balance sheet, noncontrolling interest represents the partner’s investment in the entity, plus its share of after tax profits less any cash distributions. The Company owned a controlling 51.0% legal interest and had a 62.5% economic interest in ADGNY as of December 31, 2014.
	As of December 31, 2014 and December 31, 2013, the Company owned a 50.1% and a 70.7%, interest in EuroSite Power, respectively, and has consolidated EuroSite Power into its financial statements in both years in accordance with GAAP.
	The Company has consolidated the operating results and financial position of EuroSite Power as it has determined it has a controlling financial interest in EuroSite Power. This determination was based on application of the variable interest entity (VIE) model which determines whether a controlling financial interest exists by other than majority voting ownership. In applying the VIE model, the Company considered the explicit and implicit variable interests which exist in EuroSite Power including its own and its ability to direct the activities of EuroSite Power which most significantly effect it’s economic performance and the Company’s obligation to absorb the expected losses of EuroSite Power.  In addition to its equity ownership in EuroSite Power, the Company has an implicit variable interest in EuroSite Power through its guarantee of the long term convertible indebtedness of EuroSite Power. This results in the Company’s voting ownership being disproportional to its obligation to absorb the expected losses of EuroSite Power. This combined with the fact that substantially all of EuroSite Power’s  activities either involve or are conducted on behalf of the Company results in EuroSite Power being considered a VIE.
	The current level of the Company’s ownership results in the Company’s ability to control the activities which most significantly effect the economic performance of EuroSite  Power. This combined with the Company’s obligation to absorb losses which could be significant to EuroSite Power qualify the Company as the primary beneficiary of EuroSite Power. As the primary beneficiary of a VIE, the Company is required to consolidate the operating results and financial position of the VIE.
	On July 2, 2013, the Company declared a special dividend of one share of EuroSite Power common stock for every ten shares of American DG Energy common stock (“special dividend”). The special dividend was paid on August 15, 2013, to stockholders of record as of the close of business on July 25, 2013. In connection with this transaction, the Company issued to its stockholders an aggregate of 4,880,679 shares of EuroSite Power common stock that it owns.
	The Company provides a guarantee with respect to the outstanding third party convertible indebtedness under EuroSite Power’s convertible debentures which it was not contractually obligated to provide. During 2013, the Company loaned $1,100,000 to EuroSite Power which it was not contractually obligated to do. The loan was made to facilitate deployment of new energy systems and the loan was ultimately converted into common stock of EuroSite Power. The Company also helps facilitate and assists EuroSite Power in obtaining additional sources of financing.
	The Company’s operations are comprised of one business segment. The Company’s business is selling energy in the form of electricity, heat, hot water and cooling to its customers under long-term sales agreements. The Company’s revenue is generated in the United States of America and in the United Kingdom. During the years ended December 31, 2014 and 2013 revenue generated in the United States amounted to $6,989,680 and $6,623,001, respectively, and revenue generated in the United Kingdom amounted to $1,577,873 and $838,879 respectively.  At December 31, 2014, $18,536,250 of the Company’s long lived assets were located in the United States of America and $6,348,905 were located in the United Kingdom.  At December 31, 2013, $17,900,959 of the Company’s long lived assets were located in the United States of America and $4,030,330 were located in the United Kingdom.
	The Company has experienced total net losses since inception of approximately $35.2 million. For the foreseeable future, the Company expects to experience continuing operating losses and negative cash flows from operations as its management executes the current business plan. The Company believes that its existing resources, including cash and cash equivalents and future cash flow from operations, are sufficient to meet the working capital requirements of its existing business for the foreseeable future, including the next twelve months; however, as the Company continues to grow its business by adding more energy systems, the cash requirements will increase. Beyond March 31, 2016, the Company may need to raise additional capital through a debt financing or an equity offering to meet its operating and capital needs. There can be no assurance, however, that the Company will be successful in its fundraising efforts or that additional funds will be available on acceptable terms, if at all.
	In 2014, the Company raised $8,453,717, net of issuance costs, share repurchases and distributions, from the sale of the Company and its subsidiary's common stock, its subsidiaries loans and convertible debt. If the Company is unable to raise additional capital in 2016 it may need to terminate certain of its employees and adjust its current business plan. Financial considerations may cause the Company to modify planned deployment of new energy systems and may decide to suspend installations until it is able to secure additional working capital. The Company will evaluate possible acquisitions of, or investments in, businesses, technologies and products that are complementary to its business; however, the Company is not currently engaged in such discussions.
Use of Estimates	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Revenue Recognition	Revenue from energy contracts is recognized when electricity, heat, and chilled water is produced by the cogeneration systems on-site. The Company bills each month based on various meter readings installed at each site. The amount of energy produced by on-site energy systems is invoiced, as determined by a contractually defined formula. Under certain energy contracts, the customer directly acquires the fuel to power the systems and receives credit for that expense from the Company. The credit is recorded as a cost of sale. Revenues from operations, including shared savings are recorded when provided and verified. Maintenance service revenue is recognized over the term of the agreement and is billed on a monthly basis in arrears.
	In some cases, the customer may choose to own the energy system rather than have it owned by American DG Energy. In this case, the Company accounts for revenue, or turnkey revenue, and costs using the percentage-of-completion method of accounting. Under the percentage-of-completion method of accounting, revenues are recognized by applying percentages of completion to the total estimated revenues for the respective contracts. Costs are recognized as incurred. The percentages of completion are determined by relating the actual cost of work performed to date to the current estimated total cost at completion of the respective contracts. When the estimate on a contract indicates a loss, the Company records the entire expected loss, regardless of the percentage of completion. The excess of contract costs and profit recognized to date on the percentage-of-completion accounting method in excess of billings is recorded as unbilled revenue. Billings in excess of related costs and estimated earnings is recorded as deferred revenue.
	Customers may buy out their long-term obligation under energy contracts and purchase the underlying equipment from the Company. Any resulting gain on these transactions is recognized over the payment period in the accompanying consolidated statements of operations.
	The Company is able to participate in the demand response market and receive payments due to the availability of its energy systems. Demand response programs provide payments for either the reduction of electricity usage or the increase in electricity production during periods of peak usage throughout a utility territory.
Cash and Cash Equivalents	The Company considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. The Company has cash balances in certain financial institutions in amounts which occasionally exceed current federal deposit insurance limits. The financial stability of these institutions is continually reviewed by senior management. The Company believes it is not exposed to any significant credit risk on cash and cash equivalents.
Concentrations and Credit Risk	Financial instruments, which potentially subject the Company to concentrations of credit risk, consist of highly liquid cash equivalents and trade receivables. The Company’s cash equivalents are placed with certain financial institutions and issuers.
Accounts Receivable	The Company maintains receivable balances primarily with customers located throughout New York, New Jersey and the United Kingdom. The Company reviews its customers’ credit history before extending credit and generally does not require collateral. An allowance for doubtful accounts is established based upon factors surrounding the credit risk of specific customers, historical trends and other information. Generally, such losses have been within management’s expectations. Bad debt is written off when identified
Inventory	Inventories are stated at the lower of cost or market, valued on a first-in, first-out basis. Inventory is reviewed periodically for slow-moving and obsolete items.
Supply Concentrations	Most of the Company’s cogeneration unit purchases for the years ended December 31, 2014 and 2013 were from one vendor (see “Note 8 - Related parties”). The Company believes there are sufficient alternative vendors available to ensure a constant supply of cogeneration units on comparable terms. However, in the event of a change in suppliers, there could be a delay in obtaining units which could result in a temporary slowdown of installing additional income producing sites. In addition, the majority of the Company’s units are installed and maintained by the noncontrolling interest holder or maintained by Tecogen Inc., or Tecogen (see “Note 8 - Related parties”). The Company believes there are sufficient alternative vendors available to ensure a constant supply of maintenance and installation services on comparable terms. However, in the event of a change of vendor, there could be a delay in installation or maintenance services.
Property, Plant and Equipment	Property, plant and equipment are stated at cost. Depreciation and amortization are computed using the straight-line method at rates sufficient to write off the cost of the applicable assets over their estimated useful lives. Repairs and maintenance are expensed as incurred.
	The Company reviews the useful life of its energy systems on a quarterly basis or whenever events or changes in business circumstances indicate that the carrying value of the assets may not be fully recoverable or that the useful lives of the assets are no longer appropriate. The Company evaluates the recoverability of its long-lived assets when potential impairment is indicated by comparing the remaining net book value of the assets to the estimated future undiscounted cash flows attributable to such assets. The useful life of the Company’s energy systems is the lesser of the economic life of the asset or the term of the underlying contract with the customer, typically 12 to 15 years. If impairment is indicated, the asset is written down to its estimated fair value based on a discounted cash flow analysis. During 2014, the Company recorded asset impairment losses totaling $723,438 relating to certain of its energy systems as a result of changing or unexpected conditions with respect to the energy systems which impact the estimated future cash flows. The conditional changes impacting the estimated future cash flows related to these assets resulted from changes in the level of demand for electricity and/or hot water at particular installations, finalization of start-up period customization at particular installations and/or price changes in electrical and natural gas rates, all of which impacted estimated future cash flows.
	The Company receives rebates and incentives from various utility companies which are accounted for as a reduction in the book value of the assets. The rebates are payable from the utility to the Company and are applied against the cost of construction, therefore reducing the book value of the installation. As a reduction of the facility construction costs, these rebates are treated as an investing activity in the statements of cash flows. The rebates received by the Company from the utilities that apply to the cost of construction are one time rebates based on the installed cost, capacity and thermal efficiency of the installed unit and are earned upon the installation and inspection by the utility and are not related to or subject to adjustment based on the future operating performance of the installed units. The rebate agreements with utilities are based on standard terms and conditions, the most significant being customer eligibility and post-installation work verification by a specific date.
Stock-Based Compensation	Stock based compensation cost is measured at the grant date based on the estimated fair value of the award and is recognized as an expense in the consolidated statements of operations over the requisite service period. The fair value of stock options granted is estimated using the Black-Scholes option pricing valuation model. The Company recognizes compensation on a straight-line basis over the expected life for each separately vesting portion of the option award. Use of a valuation model requires management to make certain assumptions with respect to selected model inputs. Expected volatility is calculated based on the Company’s historic volatility over the expected life of the option grant. The average expected life is estimated using the simplified method for “plain vanilla” options. The simplified method determines the expected life in years based on the vesting period and contractual terms as set forth when the award is made. The Company uses the simplified method for awards of stock-based compensation since it does not have the necessary historical exercise and forfeiture data to determine an expected life for stock options. The risk-free interest rate is based on U.S. Treasury zero-coupon issues with a remaining term which approximates the expected life assumed at the date of grant. When options are exercised the Company normally issues new shares.
Loss per Common Share	The Company computes basic loss per share by dividing net income (loss) for the period by the weighted average number of shares of common stock outstanding during the period. The Company computes diluted earnings per common share using the treasury stock method. For purposes of calculating diluted earnings per share, the Company considers its shares issuable in connection with convertible debentures, stock options and warrants to be dilutive common stock equivalents when the exercise price is less than the average market price of its common stock for the period. For the year ended December 31, 2014, the Company excluded 15,763,083 anti-dilutive shares resulting from exercise of stock options, warrants and shares issuable in connection with convertible debentures, and for the year ended December 31, 2013, the Company excluded 12,088,313 anti-dilutive shares resulting from exercise of stock options, warrants and unvested restricted stock. All shares issuable for both years were anti-dilutive because of the reported net loss.
Income Taxes	As part of the process of preparing its consolidated financial statements, the Company is required to estimate its income taxes in each of the jurisdictions in which it operates. This process involves the Company estimating its actual current tax exposure together with assessing temporary differences resulting from differing treatment of items, such as depreciation and certain accrued liabilities for tax and accounting purposes. These differences result in deferred tax assets and liabilities, which are included within the Company’s consolidated balance sheet. The Company must then assess the likelihood that its deferred tax assets will be recovered from future taxable income and to the extent it believes that recovery is not likely, the Company must establish a valuation allowance.
	The Company is allowed to recognize the tax benefits of uncertain tax positions only where the position is “more likely than not” to be sustained assuming examination by tax authorities. The amount recognized is the amount that represents the largest amount of tax benefit that is greater than 50.0% likely of being ultimately realized. A liability is recognized for any benefit claimed, or expected to be claimed, in a tax return in excess of the benefit recorded in the financial statements, along with any interest and penalties (if applicable) on that excess.
	The tax years 2003 through 2013 remain open to examination by major taxing jurisdictions to which the Company is subject, which are primarily in the United States, as carry forward attributes generated in years past may still be adjusted upon examination by the Internal Revenue Service or state tax authorities if they are or will be used in a future period. The Company is currently not under examination by the Internal Revenue Service or any other jurisdiction for any tax years. The Company did not recognize any interest and penalties associated with unrecognized tax benefits in the accompanying consolidated financial statements. The Company would record any such interest and penalties as a component of interest expense. The Company does not expect any material changes to the unrecognized benefits within twelve months of the reporting date.
Fair Value of Financial Instruments	The Company’s financial instruments are cash and cash equivalents, short-term investments, accounts receivable, accounts payable, convertible debentures and amounts due to/from related parties. The recorded values of cash and cash equivalents, accounts receivable, accounts payable and amounts due to/from related parties approximate their fair values based on their short-term nature. The warrant liability is recorded at fair value. The loan payable to related party is at fair value. The carrying value of the convertible debentures on the balance sheet at December 31, 2014 approximates fair value as the terms approximate those currently available for similar instruments.
Impact of New Accounting Pronouncements	In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606),” to clarify the principles for recognizing revenue and to develop a common revenue standard for GAAP and the International Financial Reporting Standards. This guidance supersedes previously issued guidance on revenue recognition and gives a five step process an entity should follow so that the entity recognizes revenue that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This new guidance will be effective for our fiscal 2017 reporting period and must be applied either retrospectively during each prior reporting period presented or retrospectively with the cumulative effect of initially applying this guidance recognized at the date of the initial application. Early adoption is not permitted. We are currently evaluating the impact of the adoption of this ASU on our consolidated financial statements.
	In August 2014, the FASB issued ASU 2014-15 "Presentation of Financial Statements-Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern". The new standard provides guidance around management's responsibility to evaluate whether there is substantial doubt about an entity's ability to continue as a going concern and to provide related footnote disclosures. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016. Early adoption is permitted. The adoption of this ASU is not expected to have a material impact on our consolidated financial statements.

Property_plant_and_equipment_T

Property, plant and equipment (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, plant and equipment consist of the following as of December 31, 2014 and 2013, respectively:
		2014			2013
	Energy systems	$	31,185,095		$	25,567,808
	Computer equipment and software	132,543			122,853
	Furniture and fixtures	87,051			85,079
	Vehicles	226,018			243,139
		31,630,707			26,018,879
	Less — accumulated depreciation	(9,509,344		)	(7,621,242		)
		22,121,363			18,397,637
	Construction in progress	2,763,792			3,533,652
		$	24,885,155		$	21,931,289

Convertible_debentures_Tables

Convertible debentures (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Fair Value Measurements Assumptions	This debt discount is being amortized over the remaining term of the debt. In accordance with ASC 820, the fair value of the conversion option at the date of modification was determined by utilizing a binomial lattice model with the following key assumptions:
	Company stock price	$1.64 per share
	Risk -free rate	1.43% - 1.45%
	Term	4.78 years
	Volatility	68.80%
	Dividend yield	—%
Convertible Debt	The face amount of convertible debentures and the related premium or discount are as follows as of December 31, 2014 and 2013, respectively:
		2014
		American DG Energy			EuroSite Power			Total
	Face amount	$	19,400,000		$	2,400,000		$	21,800,000
	Premium (discount)	(4,523,051		)	232,710			(4,290,341		)
		14,876,949			2,632,710			17,509,659
	Less amounts due to related parties	(14,876,949		)	(987,266		)	(15,864,215		)
		$	—		$	1,645,444		$	1,645,444
		2013
		American DG Energy			EuroSite Power			Total
	Face amount	$	19,400,000		$	4,000,000		$	23,400,000
	Premium (discount)	(601,620		)	—			(601,620		)
	Elimination	—			(1,100,000		)	(1,100,000		)
		18,798,380			2,900,000			21,698,380
	Less amounts due to related parties	(18,798,380		)	(1,100,000		)	(19,898,380		)
		$	—		$	1,800,000		$	1,800,000

Stockholders_equity_Tables

Stockholders' equity (Tables)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule Of Warrants Activity	Warrant activity for the years ended December 31, 2014 and 2013 was as follows:
		Number of			Weighted Average
		Warrants			Exercise Price
	Balance, December 31, 2012	565,500			$	3.19
	Granted	—			—
	Exercised	—			—
	Expired	(58,000	)		3
	Balance, December 31, 2013	507,500			$	3.24
	Granted	2,942,270			1.89
	Exercised	—			—
	Expired	—			—
	Balance, December 31, 2014	3,449,770			$	2.09
Summary of Fair Value Stock Option Assumptions	The weighted average assumptions used in the Black-Scholes option pricing model are as follows:
		2014			2013
	Stock options and restricted stock awards
	Expected life	6.25 years			5 years
	Risk-free interest rate	2.03	%		1.75	%
	Expected volatility	68.8	%		60.3	%
American DG Energy
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Share-based Compensation, Stock Options, Activity	Stock option activity for the years ended December 31, 2014 and 2013 was as follows:
	Common Stock Options	Number of Options		Weighted Average Exercise Price			Weighted Average Remaining Life	Aggregate Intrinsic Value
	Outstanding, December 31, 2013	2,386,500		$	1.49		4.13 years	$	1,092,550
	Granted	1,069,000		1
	Exercised	—		—
	Canceled	(286,500	)	1.72
	Expired	(50,000	)	0.7
	Outstanding, December 31, 2014	3,119,000		$	1.32		5.15 years	$	25,600
	Exercisable, December 31, 2014	1,360,250		$	1.5			$	—
	Vested and expected to vest, December 31, 2014	3,119,000		$	1.32			$	25,600
Schedule of Changes in the Company's Ownership Interest in its Subsidiary	The following schedule discloses the effects of changes in the Company's ownership interest in its subsidiary EuroSite Power on the Company's equity for the year ended December 31, 2014:
	Net loss attributable to American DG Energy Inc.		$	(5,888,894	)
	Transfers (to) from noncontrolling interest:
	Increase in American DG Energy Inc.'s additional paid-in capital for exchange of 9,409,000 EuroSite Power common shares for current and future interest related to the Company's convertible debentures (see "Note 4 Convertible debentures")		4,704,500
	Increase in American DG Energy Inc.'s additional paid-in-capital for sale by EuroSite Power of 3,000,000 common shares and warrants		1,486,329
	Decrease in American DG Energy Inc.'s additional paid-in-capital for reacquisition by EuroSite Power of 100,000 of its common shares		(42,902		)
	Increase in American DG Energy Inc.'s additional paid-in-capital for conversion of EuroSite Power convertible debentures into 6,100,000 common shares of EuroSite Power		2,455,377
	Noncontrolling interest share of transactions affecting subsidiary ownership		(2,718,159		)
	Subtotal transfers (to) from noncontrolling interest		5,885,145
	Change from net loss attributable to American DG Energy Inc. and transfers (to) from noncontrolling interest		$	(3,749	)
EuroSite Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Share-based Compensation, Stock Options, Activity	Stock option activity for the year ended December 31, 2014 was as follows:
	Common Stock Options	Number of Options		Weighted Average Exercise Price			Weighted Average Remaining Life		Aggregate Intrinsic Value
	Outstanding, December 31, 2013	4,025,000		$	0.87		7.58 years		$	74,000
	Granted	520,000		0.65
	Exercised	—		—
	Canceled	(240,000	)	0.49
	Expired	—		—			—		—
	Outstanding, December 31, 2014	4,305,000		$	0.87		6.84 years		$	9,800
	Exercisable, December 31, 2014	2,721,250		$	0.9				$	—
	Vested and expected to vest, December 31, 2014	4,305,000		$	0.87				$	9,800

Fair_value_measurements_Tables

Fair value measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Schedule Of Warrant Liabilities	The following table summarizes the warrant activity for the period:
		Warrant Liabilities
	Fair value at December 31, 2013	$	132,265
	Fair value adjustment at December 31, 2014	(125,485		)
	Fair value at December 31, 2014	$	6,780

Income_taxes_Tables

Income taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Reconciliation of Federal Statutory Income Tax Provision to Company's Actual Provision	econciliation of federal statutory income tax provision to the Company’s actual provision for the years ended December 31, 2014 and 2013, respectively, are as follows:
		2014			2013
	Benefit at federal statutory tax rate	$	(2,222,000	)	$	(1,647,000	)
	Foreign rate differential	159,000			141,330
	UK Energy Incentives	(649,000		)	—
	Unbenefited operating losses	2,062,960			1,505,670
	Provision for income taxes	4,000			13,450
	Income tax provision	$	(645,040	)	$	13,450
Schedule of Deferred Tax Assets	The component of net deferred tax assets recognized in the accompanying balance sheets at December 31, 2014 and 2013, respectively, are as follows:
		2014			2013
	Net operating loss carryforwards	$	10,838,000		$	9,902,000
	Accrued expenses and other	100,000			200,000
	Stock compensation	1,194,000			1,014,000
	Depreciation	(216,000		)	(516,000		)
		11,916,000			10,600,000
	Valuation allowance	(11,916,000		)	(10,600,000		)
	Net deferred tax asset	$	—		$	—

The_Company_Details

The Company (Details)	12 Months Ended
	Dec. 31, 2014
Schedule of Energy Operations [Line Items]
Number Of Energy Systems Installed	123
Minimum
Schedule of Energy Operations [Line Items]
Length of long-term energy sales agreements	10
Maximum
Schedule of Energy Operations [Line Items]
Length of long-term energy sales agreements	15

Summary_of_significant_account2

Summary of significant accounting policies (Details) (USD $)	0 Months Ended		12 Months Ended		0 Months Ended
	Jul. 02, 2013	Dec. 09, 2010	Dec. 31, 2014	Dec. 31, 2013	Oct. 03, 2014
			segment
Subsidary or Equity Method Investee [Line Items]
Net Cash Provided by (Used in) Financing Activities			$8,453,717	$3,584,684
Percentage Of Economic Interest			62.50%
Warrants Issued During Period		500,000
Stock Issued During Period, Shares, Other	4,881,000
Number of Operating Segments			1
Revenue, Net			8,567,553	7,461,880
EuroSite Power
Subsidary or Equity Method Investee [Line Items]
Paid-in-Kind Interest, Shares					1,164,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights					1,164,000
Eurosite Power Inc
Subsidary or Equity Method Investee [Line Items]
Percentage Of Ownership In Subsidiary			50.10%	70.70%
Origination of Notes Receivable from Related Parties				1,100,000
American DG New York, LLC
Subsidary or Equity Method Investee [Line Items]
Percentage Of Ownership In Joint Venture			51.00%
UNITED STATES
Subsidary or Equity Method Investee [Line Items]
Revenue, Net			6,989,680	6,623,001
Long-Lived Assets			18,536,250	17,900,959
UNITED KINGDOM
Subsidary or Equity Method Investee [Line Items]
Revenue, Net			1,577,873	838,879
Long-Lived Assets			6,348,905	4,030,330
Convertible Debt | EuroSite Power
Subsidary or Equity Method Investee [Line Items]
Convertible Debt			$3,050,000
Conversion of Stock, Shares Issued			6,100,000

Summary_of_significant_account3

Summary of significant accounting policies (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Net losses since inception	($35,232,411)	($29,343,517)
Revenue recognized from demand response activity	247,518	112,405
Maximum maturity period for highly liquid investments	3 months
Cash and Cash Equivalents concentration risk	$10,771,457
Antidilutive shares excluded from computation of loss per share (shares)	15,763,083	12,088,313

Summary_of_significant_account4

Summary of significant accounting policies (Accounts Receivable and Payble) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
	customer	customer
Concentration Risk [Line Items]
Allowance for Doubtful Accounts Receivable	112,000	183,201
Customer Concentration Risk | Accounts Receivable
Concentration Risk [Line Items]
Number Of Major Customers	4	4
Percentage of concentration	27.00%	35.00%
Customer Concentration Risk | Sales
Concentration Risk [Line Items]
Number Of Major Customers		4
Percentage of concentration	11.00%	12.00%

Summary_of_significant_account5

Summary of significant accounting policies (Accounts Payable and Supply Concentrations) (Details) (Supplier Concentration Risk)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
	vendor	vendor
Concentration Risk [Line Items]
Number of Major Vendors	1	1
Accounts Payable
Concentration Risk [Line Items]
Number of Major Vendors		4
Purchases
Concentration Risk [Line Items]
Number of Major Vendors		4

Summary_of_significant_account6

Summary of significant accounting policies (Property and Equipment) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Non-cash site impairments	$723,438	$0
Amount of grant awards received under The American Recovery And Reinvestment Act	27,500
Rebates applied to cost of construction		285,718
Energy Systems
Property, Plant and Equipment [Line Items]
Non-cash site impairments	$723,438
Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	12 years
Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	15 years

Property_plant_and_equipment_S

Property, plant and equipment (Summary of Property, Plant and Equipment) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$31,630,707	$26,018,879
Less ----- accumulated depreciation	-9,509,344	-7,621,242
Property, plant and equipment, before contruction in progress	22,121,363	18,397,637
Construction in progress	2,763,792	3,533,652
Property, plant and equipment, net	24,885,155	21,931,289
Energy Systems
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	31,185,095	25,567,808
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	132,543	122,853
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	87,051	85,079
Vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$226,018	$243,139

Property_plant_and_equipment_D

Property, plant and equipment (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Abstract]
Depreciation expense	$1,888,102	$1,471,914

Convertible_debentures_Details

Convertible debentures (Details) (USD $)	0 Months Ended									12 Months Ended		0 Months Ended
	Oct. 03, 2014	25-May-14	Nov. 25, 2013	Aug. 15, 2013	Jul. 02, 2013	25-May-13	Jan. 10, 2013	Nov. 30, 2011	23-May-11	Dec. 31, 2014	Dec. 31, 2013	Jul. 02, 2013
Debt Instrument [Line Items]
Long-term Debt									$12,500,000
Debt Instrument, Maturity Date								25-May-18	25-May-18
Debt Instrument, Interest Rate, Effective Percentage								6.00%	6.00%
Debt Instrument, Convertible, Conversion Price (in dollars per share)				$2.11				$2.20	$2.20
Percentage Of Option To Redeem Par Value								115.00%	115.00%
Line of Credit Facility, Amount Outstanding									2,400,000
Due to related party								6,900,000		630,805	178,216
Debt Instrument, Periodic Payment, Interest		582,000	582,000			582,000
Common stock, shares issued		260,154	377,391			316,462				52,140,001	49,817,920
Common stock, par value (usd per share)		$2.24	$1.54			$1.84				$0.00	$0.00
Non-cash interest (interest) expense, adjusted for the difference between the average stock price and the fair market value						53,511
Number of business days used to determine the average daily closing price of the Company's common stock							10 days
Reduction in non-cash interest expense adjusted for the difference between the average stock price and the fair market value		42,368	59,562
Stock Issued During Period, Shares, Other					4,881,000
Stockholders' Equity Note, Stock Split, Holding Period					6 months
Debt Instrument, Convertible, Conversion Ratio				0.06
Long-term Debt, Gross				19,400,000
Debt Instrument, Convertible, Conversion Price, Prior (in dollars per share)				$2.20
Debt Instrument, Repurchased Face Amount				649,000
Interest on convertible debentures paid in stock of subsidiary										585,718	0
Non-cash debt discount (Issuance of subsidiary common stock in conjunction with prepayment of interest on and exchange of convertible debentures)										4,207,411	0
Class of Warrant or Right, Term	3 years
Class of Warrant or Right, Exercise Price of Warrants or Rights	$0.60
Fair value of warrant exchanged for future convertible debenture interest	84,911									84,911	0
Conversion of convertible debenture interest to common stock										4,207,411
Convertible Debentures 2010
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage To Fully Accrete To Face Value										7.80%
Convertible Debt
Debt Instrument [Line Items]
Face amount										21,800,000	23,400,000
Debt Instrument, Unamortized Discount										4,523,051
Amortization of Debt Discount (Premium)										162,486
Convertible Debt | Convertible Debentures 2010
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage										6.00%
Common Stock
Debt Instrument [Line Items]
Stockholders' Equity Note, Stock Split, Conversion Ratio												10
EuroSite Power
Debt Instrument [Line Items]
Paid-in-Kind Interest, Shares	1,164,000
Interest on convertible debentures paid in stock of subsidiary	582,000
Paid-in-Kind Interest, Shares, Prepayment	8,245,000
Non-cash debt discount (Issuance of subsidiary common stock in conjunction with prepayment of interest on and exchange of convertible debentures)	4,122,500
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	1,164,000
EuroSite Power | Convertible Debt
Debt Instrument [Line Items]
Debt Instrument, Convertible, Conversion Price (in dollars per share)										$0.50
Face amount										2,400,000	4,000,000
Noncontrolling Interest
Debt Instrument [Line Items]
Non-cash debt discount (Issuance of subsidiary common stock in conjunction with prepayment of interest on and exchange of convertible debentures)										$84,911

Convertible_debentures_Fair_va

Convertible debentures (Fair value assumptions) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Sep. 04, 2013	Aug. 28, 2013
Debt Instrument [Line Items]
Company stock price	$1.64	$1.50	$1.55
Term	4 years 9 months 11 days
Volatility	68.80%
Minimum
Debt Instrument [Line Items]
Risk -free rate	1.43%
Maximum
Debt Instrument [Line Items]
Risk -free rate	1.45%

Convertible_debentures_Eurosit

Convertible debentures (Eurosite Power Convertible Debenture) (Details) (USD $)

0 Months Ended

12 Months Ended

0 Months Ended

1 Months Ended

Aug. 15, 2013

Dec. 31, 2014

Dec. 31, 2013

Apr. 15, 2014

Jun. 14, 2013

Oct. 03, 2014

Mar. 31, 2013

Sep. 04, 2013

Aug. 28, 2013

Nov. 30, 2011

23-May-11

Feb. 20, 2014

Debt Instrument [Line Items]

Loss on extinguishment of debt

($533,177)

$0

Long-term Debt, Gross

19,400,000

Debt Instrument, Unamortized Premium

232,710

Debt Instrument, Convertible, Conversion Price

$2.11

$2.20

$2.20

Debt Instrument, Convertible, Conversion Ratio

0.06

Company stock price

$1.64

$1.50

$1.55

Volatility

68.80%

Induced Conversion of Convertible Debt Expense

324,977

0

Amortization

127,554

Convertible Debt

Debt Instrument [Line Items]

Face amount

21,800,000

23,400,000

Convertible Debt | Senior Convertible Notes Due 2017

Debt Instrument [Line Items]

Face amount

1,000

Debt Instrument, Interest Rate, Stated Percentage

400.00%

Loss on extinguishment of debt

-713,577

Extinguishment of Debt, Amount

180,400

Long-term Debt, Gross

4,000,000

Debt Instrument, Unamortized Premium

180,400

Debt Instrument, Convertible, Conversion Price

$0.60

Debt Instrument, Convertible, Conversion Ratio

1,667

Company stock price

$0.51

Volatility

87.00%

Risk -free rate

0.90%

Fair Value Assumptions, Expected Dividend Rate

0.00%

Convertible Debt | Note 1 300K Senior Convertible Note Due 2018

Debt Instrument [Line Items]

Face amount

1,450,000

Debt Instrument, Interest Rate, Stated Percentage

4.00%

Debt Instrument, Term

4 years

Debt Instrument, Convertible, Conversion Price

$0.60

EuroSite Power

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

1,100,000

Registration Rights Percentage

30.00%

Registration Rights, Offering Price, Net

250,000

EuroSite Power | Senior Unsecured Convertible Notes Due 2015

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

1,100,000

Debt Instrument, Interest Rate, Stated Percentage

6.00%

EuroSite Power | Senior Convertible Notes Due 2017

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

1,100,000

EuroSite Power | Unsecured Debt | Senior Unsecured Convertible Notes Due 2015

Debt Instrument [Line Items]

Face amount

4,000,000

Debt Instrument, Interest Rate, Stated Percentage

4.00%

Debt Instrument, Convertible, Shares

1,000

Debt Instrument, Convertible, Conversion Rate Denominator

1,000

Debt Instrument, Extension Period

3 years

Debt Instrument, Interest Rate, Increase (Decrease)

-3.00%

Debt Instrument, Term

3 years

EuroSite Power | Convertible Debt

Debt Instrument [Line Items]

Face amount

2,400,000

4,000,000

Extinguishment of Debt, Amount

3,050,000

Debt Instrument, Convertible, Conversion Price

$0.50

Convertible Debt

3,050,000

Conversion of Stock, Shares Issued

6,100,000

EuroSite Power | Convertible Debt | Senior Convertible Notes Due 2017

Debt Instrument [Line Items]

Face amount

4,000,000

Debt Instrument, Interest Rate, Stated Percentage

4.00%

Debt Instrument, Convertible, Shares

1,667

Debt Instrument, Convertible, Conversion Rate Denominator

1,000

Long-term Debt, Fair Value

4,656,000

Long-term Debt, Gross

4,000,000

Debt Instrument, Unamortized Premium

656,000

Prepayment from Related Party for Future Purchases

Debt Instrument [Line Items]

Related party transaction, discount rate

6.00%

Prepayment from Related Party for Future Purchases | EuroSite Power

Debt Instrument [Line Items]

Related party transaction, discount rate

6.00%

Bruno Meier | EuroSite Power | Senior Unsecured Convertible Notes Due 2015

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

250,000

Bruno Meier | EuroSite Power | Senior Convertible Notes Due 2017

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

250,000

Joan Giacinti | EuroSite Power | Senior Unsecured Convertible Notes Due 2015

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

300,000

Joan Giacinti | EuroSite Power | Senior Convertible Notes Due 2017

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

300,000

Charles T. Maxwell | EuroSite Power | Senior Unsecured Convertible Notes Due 2015

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

250,000

Charles T. Maxwell | EuroSite Power | Senior Convertible Notes Due 2017

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

250,000

Nettlestone Enterprises Limited | EuroSite Power | Senior Unsecured Convertible Notes Due 2015

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

300,000

Nettlestone Enterprises Limited | EuroSite Power | Senior Convertible Notes Due 2017

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

300,000

Perastra Management Management S.A | EuroSite Power | Senior Convertible Notes Due 2017

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

1,500,000

Yves Micheli | EuroSite Power | Senior Convertible Notes Due 2017

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

$300,000

Convertible_debentures_Summary

Convertible debentures (Summary of Debt) (Details) (Convertible Debt, USD $)	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Face amount	$21,800,000	$23,400,000
Premium (discount)	-4,290,341	-601,620
Convertible Debt, Noncurrent, Excluding Amount Due To Related Party	17,509,659	21,698,380
Less amounts due to related parties	-15,864,215	-19,898,380
Convertible Debt, Noncurrent, Including Amount Due To Related Party	1,645,444	1,800,000
American DG Energy
Debt Instrument [Line Items]
Face amount	19,400,000	19,400,000
Premium (discount)	-4,523,051	-601,620
Convertible Debt, Noncurrent, Excluding Amount Due To Related Party	14,876,949	18,798,380
Less amounts due to related parties	-14,876,949	-18,798,380
Convertible Debt, Noncurrent, Including Amount Due To Related Party	0	0
EuroSite Power
Debt Instrument [Line Items]
Face amount	2,400,000	4,000,000
Premium (discount)	232,710	0
Convertible Debt, Noncurrent, Excluding Amount Due To Related Party	2,632,710	2,900,000
Less amounts due to related parties	-987,266	-1,100,000
Convertible Debt, Noncurrent, Including Amount Due To Related Party	1,645,444	1,800,000
Consolidation, Eliminations
Debt Instrument [Line Items]
Less amounts due to related parties		-1,100,000
Consolidation, Eliminations | American DG Energy
Debt Instrument [Line Items]
Less amounts due to related parties		0
Consolidation, Eliminations | EuroSite Power
Debt Instrument [Line Items]
Less amounts due to related parties		($1,100,000)

Stockholders_equity_Details

Stockholders' equity (Details) (USD $)

0 Months Ended

12 Months Ended

0 Months Ended

Sep. 04, 2013

Aug. 28, 2013

Dec. 09, 2010

Dec. 31, 2014

Dec. 31, 2013

Oct. 15, 2013

Mar. 20, 2013

Aug. 06, 2014

Oct. 03, 2014

Dec. 31, 2011

Jun. 13, 2011

Jun. 11, 2011

Class of Stock [Line Items]

Proceeds From Sale Of Restricted Common Stock

$500,001

$465,000

Stock Issued During Period Shares Restricted Stock

333,334

Company stock price

$1.50

$1.55

$1.64

Common stock, shares outstanding

52,140,001

49,817,920

Number of Warrants Outstanding (in shares)

3,449,770

507,500

565,500

Share-based Compensation

475,899

596,349

Fair Value Assumptions Risk Free Interest Rate

2.03%

1.75%

Expected volatility

68.80%

60.30%

Warrants Expiration Term

5 years

Class of Warrant or Right, Exercise Price of Warrants or Rights

$0.60

Proceeds from Issuance of Common Stock

3,269,275

952,333

Stock Options

Class of Stock [Line Items]

Options Granted in Period, Weighted Average Grant Date Fair Value

$0.63

$0.86

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross

430,000

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value

678,570

368,044

Total Compensation Cost Not yet Recognized, Stock Options

836,429

740,221

American DG Energy

Class of Stock [Line Items]

Number of Shares Authorized

8,000,000

Total Compensation Cost Not yet Recognized

696,870

Nonvested Awards, Weighted Average Period That Total Compensation Costs Will Be Recognized

1 year 0 months

Number of Non-qualified Options Issued in Period

350,000

Exercise price per share Granted Lower Range (usd per share)

$1.54

Exercise price per share Granted Upper Range (usd per share)

$1.67

Allocated Share-based Compensation Expense

310,900

315,245

Share Based Compensation Arrangement By Share Based Payment Award Options Canceled In Period

-286,500

Number of Options Expired (in shares)

-50,000

Options Issued, Fair Value

368,044

Options Granted in Period, Weighted Average Grant Date Fair Value

$0.86

Number of Options Granted (in shares)

1,069,000

Weighted Average Exercise Price Granted (usd per share)

$1

Weighted Average Remaining Life Outstanding

5 years 1 month 25 days

4 years 1 month 17 days

Number of Options Outstanding (in shares)

3,119,000

2,386,500

American DG Energy | Stock Options

Class of Stock [Line Items]

Expiration Period

10 years

American DG Energy | Minimum

Class of Stock [Line Items]

Vesting Period

2 years

American DG Energy | Minimum | Stock Options

Class of Stock [Line Items]

Vesting Period

4 years

American DG Energy | Maximum

Class of Stock [Line Items]

Vesting Period

10 years

EuroSite Power

Class of Stock [Line Items]

Capital Shares Reserved for Future Issuance

195,000

Share-based Compensation

164,999

Nonvested Awards, Weighted Average Period That Total Compensation Costs Will Be Recognized

1 year 7 months 9 days

Vesting Period

4 years

Share Based Compensation Arrangement By Share Based Payment Award Options Canceled In Period

-240,000

Number of Options Expired (in shares)

0

Number of Options Granted (in shares)

520,000

Weighted Average Exercise Price Granted (usd per share)

$0.65

Weighted Average Remaining Life Outstanding

6 years 10 months 1 day

7 years 6 months 29 days

Number of Options Outstanding (in shares)

4,305,000

4,025,000

Total Compensation Cost Not yet Recognized, Stock Options

139,559

Class of Warrant or Right, Number of Securities Called by Warrants or Rights

1,164,000

EuroSite Power | Stock Compensation Plan

Class of Stock [Line Items]

Number of Shares Authorized

4,500,000

3,000,000

EuroSite Power | Minimum

Class of Stock [Line Items]

Vesting Period

4 years

4 years

Weighted Average Exercise Price Granted (usd per share)

$0.40

EuroSite Power | Maximum

Class of Stock [Line Items]

Vesting Period

10 years

10 years

Weighted Average Exercise Price Granted (usd per share)

$0.89

Director | American DG Energy

Class of Stock [Line Items]

Number of Non-qualified Options Issued in Period

80,000

Charles T. Maxwell

Class of Stock [Line Items]

Stock Issued During Period Shares Restricted Stock

300,000

Company stock price

$0.00

Employee | EuroSite Power

Class of Stock [Line Items]

Number of Options Granted (in shares)

88,000

Share-based Compensation Arrangement by Share-based Payment Award, Options, Number of Employees Granted

6

Director | EuroSite Power

Class of Stock [Line Items]

Number of Options Granted (in shares)

100,000

Consultant | EuroSite Power

Class of Stock [Line Items]

Number of Options Granted (in shares)

50,000

Executive Officer | EuroSite Power

Class of Stock [Line Items]

Number of Options Granted (in shares)

200,000

Common Stock

Class of Stock [Line Items]

Stock Issued During Period, Shares, New Issues

2,650,000

Three And Five Year Warrants

Class of Stock [Line Items]

Proceeds from Issuance of Common Stock

3,269,275

Three Year Warrants

Class of Stock [Line Items]

Warrants Expiration Term

3 years

Class of Warrant or Right, Number of Securities Called by Warrants or Rights

2,829,732

Five Year Warrants

Class of Stock [Line Items]

Warrants Expiration Term

5 years

Class of Warrant or Right, Outstanding

112,538

Class of Warrant or Right, Exercise Price of Warrants or Rights

1.8875

Stockholders_equity_Class_of_R

Stockholders' equity (Class of Rights and Warrants) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2011
Equity [Abstract]
Number of Warrants Granted (in shares)	2,942,270	0
Number of Warrants Outstanding (in shares)	3,449,770	507,500	565,500

Stockholders_equity_Summary_of

Stockholders' equity (Summary of Warranty Activity) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2011
Number of Warrants Outstanding [Roll Forward]
Number of Warrants Outstanding, Beginning (in shares)	507,500		565,500
Number of Warrants Granted (in shares)	2,942,270	0
Number of Warrants Exercised (in shares)	0	0
Number of Warrants Expired (in shares)	0	-58,000
Number of Warrants Outstanding, Ending (in shares)	3,449,770	507,500	565,500
Weighted Average Grant Date Fair Value [Roll Forward]
Weighted Average Grant Date Fair Value Outstanding, Beginning (usd per share)	$3.24		$3.19
Weighted Average Grant Date Fair Value Granted (usd per share)	$1.89	$0
Weighted Average Grant Date Fair Value Exercised (usd per share)	$0	$0
Weighted Average Grant Date Fair Value Expired (usd per share)	$0	$3
Weighted Average Grant Date Fair Value Outstanding, Ending (usd per share)	$2.09	$3.24	$3.19

Stockholders_equity_Summary_of1

Stockholders' equity (Summary of Weighted Average Assumptions Used In Black Scholes Option Pricing Model) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Equity [Abstract]
Expected life	6 years 3 months	5 years
Risk-free interest rate	2.03%	1.75%
Expected volatility	68.80%	60.30%

Stockholders_equity_Summary_of2

Stockholders' equity (Summary of Stock Option Activity) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
American DG Energy
Stock Options, Outstanding [Roll Forward]
Number of Options Outstanding Beginning (in shares)	2,386,500
Number of Options Granted (in shares)	1,069,000
Number of Options Exercised (in shares)	0
Number of Options Canceled (in shares)	-286,500
Number of Options Expired (in shares)	-50,000
Number of Options Outstanding, Ending (in shares)	3,119,000	2,386,500
Number of Option Exercisable, December 31, 2013 (in shares)	1,360,250
Number of Option Vested and expected to vest, December 31, 2013 (in shares)	3,119,000
Weighted Average Exercise Price [Roll Forward]
Weighted Average Exercise Price Outstanding, Beginning (usd per share)	$1.49
Weighted Average Exercise Price Granted (usd per share)	$1
Weighted Average Exercise Price Exercised (usd per share)	$0
Weighted Average Exercise Price Cancelled (usd per share)	$1.72
Weighted Average Exercise Price Expired (usd per share)	$0.70
Weighted Average Exercise Price Outstanding, Ending (usd per share)	$1.32	$1.49
Weighted Average Exercise Price Exercisable, December 31, 2013 (usd per share)	$1.50
Weighted Average Exercise Price Vested and expected to vest, December 31, 2013 (usd per share)	$1.32
Options, Additional Disclosures [Abstract]
Weighted Average Remaining Life Outstanding, Beginning	5 years 1 month 25 days	4 years 1 month 17 days
Weighted Average Remaining Life Outstanding, Ending	5 years 1 month 25 days	4 years 1 month 17 days
Aggregate Intrinsic Value Outstanding, Beginning	$1,092,550
Aggregate Intrinsic Value Outstanding, Ending	25,600	1,092,550
Aggregate intrinsic value Exercisable	0
Aggregate Intrinsic value Vested and expected to vest	25,600
EuroSite Power
Stock Options, Outstanding [Roll Forward]
Number of Options Outstanding Beginning (in shares)	4,025,000
Number of Options Granted (in shares)	520,000
Number of Options Exercised (in shares)	0
Number of Options Canceled (in shares)	-240,000
Number of Options Expired (in shares)	0
Number of Options Outstanding, Ending (in shares)	4,305,000	4,025,000
Number of Option Exercisable, December 31, 2013 (in shares)	2,721,250
Number of Option Vested and expected to vest, December 31, 2013 (in shares)	4,305,000
Weighted Average Exercise Price [Roll Forward]
Weighted Average Exercise Price Outstanding, Beginning (usd per share)	$0.87
Weighted Average Exercise Price Granted (usd per share)	$0.65
Weighted Average Exercise Price Exercised (usd per share)	$0
Weighted Average Exercise Price Cancelled (usd per share)	$0.49
Weighted Average Exercise Price Expired (usd per share)	$0
Weighted Average Exercise Price Outstanding, Ending (usd per share)	$0.87	$0.87
Weighted Average Exercise Price Exercisable, December 31, 2013 (usd per share)	$0.90
Weighted Average Exercise Price Vested and expected to vest, December 31, 2013 (usd per share)	$0.87
Options, Additional Disclosures [Abstract]
Weighted Average Remaining Life Outstanding, Beginning	6 years 10 months 1 day	7 years 6 months 29 days
Weighted Average Remaining Life Outstanding, Ending	6 years 10 months 1 day	7 years 6 months 29 days
Aggregate Intrinsic Value Outstanding, Beginning	74,000
Aggregate Intrinsic Value Outstanding, Ending	9,800	74,000
Aggregate intrinsic value Exercisable	0
Aggregate Intrinsic value Vested and expected to vest	$9,800
EuroSite Power | Minimum
Weighted Average Exercise Price [Roll Forward]
Weighted Average Exercise Price Outstanding, Beginning (usd per share)	$0.41
Weighted Average Exercise Price Granted (usd per share)	$0.40
Weighted Average Exercise Price Cancelled (usd per share)	$0.41
Weighted Average Exercise Price Expired (usd per share)	$0
Weighted Average Exercise Price Outstanding, Ending (usd per share)	$0.45
EuroSite Power | Maximum
Weighted Average Exercise Price [Roll Forward]
Weighted Average Exercise Price Outstanding, Beginning (usd per share)	$0.90
Weighted Average Exercise Price Granted (usd per share)	$0.89
Weighted Average Exercise Price Cancelled (usd per share)	$0.90
Weighted Average Exercise Price Expired (usd per share)	$0
Weighted Average Exercise Price Outstanding, Ending (usd per share)	$0.90

Stockholders_equity_Changes_in

Stockholders' equity (Changes in Company's Ownership Interest in its Subsidiary EuroSite Power) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Subsidiary or Equity Method Investee [Line Items]
Net loss attributable to American DG Energy Inc.	($6,525,358)	($5,126,278)
Transfers (to) from noncontrolling interest:
Ownership changes to noncontrolling interest		559,500
Noncontrolling interest share of transactions affecting subsidiary ownership	-124,056
Subtotal transfers (to) from noncontrolling interest	5,885,145
Change from net loss attributable to American DG Energy Inc. and transfers (to) from noncontrolling interest	-3,749
Increase (Decrease) in Subsidiary Stock Held By Company, Shares	9,409,000
Subsidiary Common Stock and Warrants Sold, Shares	3,000,000
Reacquisition of Subsidiary Stock by Subsidiary, Shares	100,000
Conversion of Subsidiary Convertible Debentures into Subsidiary Common Stock, Shares	6,100,000
Accumulated Deficit
Subsidiary or Equity Method Investee [Line Items]
Net loss attributable to American DG Energy Inc.	-5,888,894	-4,886,672
Additional Paid-in Capital
Transfers (to) from noncontrolling interest:
Ownership changes to noncontrolling interest	4,704,500
Increase in American DG Energy Inc.'s additional paid-in-capital for sale by EuroSite Power of 3,000,000 common shares and warrants	1,486,329
Decrease in American DG Energy Inc.'s additional paid-in-capital for reacquisition by EuroSite Power of 100,000 of its common shares	-42,902
Increase in American DG Energy Inc.'s additional paid-in-capital for conversion of EuroSite Power convertible debentures into 6,100,000 common shares of EuroSite Power	2,455,377
Noncontrolling interest share of transactions affecting subsidiary ownership	($2,718,159)

Warrant_liability_Details

Warrant liability (Details) (USD $)	0 Months Ended	12 Months Ended
	Dec. 09, 2010	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Warrants Issued During Period	500,000
Warrants, Exercise Price Per Share	$3.25
Warrants Expiration Term	5 years
Warrants Expiration Date		14-Dec-15
Warrant Liability, Period to Determine Volatility Rate		30 days
Expected Volitility, Maximum Rate		70.00%

Employee_benefit_plan_Details

Employee benefit plan (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]
Maximum employer annual contribution per employee, percent	4.50%
Company contributions to the plan during the year, dollars	$49,816	$53,697

Related_parties_Details

Related parties (Details) (USD $)	1 Months Ended	12 Months Ended	1 Months Ended		12 Months Ended	0 Months Ended
	Jul. 31, 2012	Dec. 31, 2014	Mar. 31, 2013	Jan. 31, 2006	Dec. 31, 2013	Oct. 23, 2009	Sep. 19, 2014
Related Party Transaction [Line Items]
Related party transactions agreement term	1 year
Rental income related party		$6,495
Related party agreement, period for notice termination	60 days
Note payable, related party		3,000,000			0
Prepayment from Related Party for Future Purchases
Related Party Transaction [Line Items]
Related party transaction, discount rate			6.00%
Tecogen
Related Party Transaction [Line Items]
Related Party Transaction, Purchases from Related Party		1,432,801			817,700
Related party transactions agreement term				1 year
Rental income related party		6,495
Ilois
Related Party Transaction [Line Items]
Related party transactions agreement term						5 years
Charles T. Maxwell
Related Party Transaction [Line Items]
Note payable, related party							$3,000,000
Interest rate		1.85%

Fair_value_measurements_Detail

Fair value measurements (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Derivative Liabilities, Noncurrent	$6,780	$132,265
Fair Value Assumptions Expected Volatility Rate	68.80%	60.30%
Fair Value Assumptions Risk Free Interest Rate	2.03%	1.75%
Fair Value Assumptions Expected Term (in Years)	6 years 3 months	5 years
Fair Value Inputs, Discount Rate	6.00%
Fair Value, Inputs, Level 3
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair Value Assumptions Expected Volatility Rate	57.00%
Fair Value Assumptions Risk Free Interest Rate	2.08%
Fair Value Assumptions Expected Term (in Years)	5 years
Fair Value, Inputs, Level 3 | Warrant
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair Value Assumptions Expected Volatility Rate	91.40%
Fair Value Assumptions Risk Free Interest Rate	0.02%
Fair Value Assumptions Expected Term (in Years)	11 months 16 days

Fair_value_measurements_Summar

Fair value measurements (Summary of Activity for the Period) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at December 31, 2013	$132,265
Fair value adjustment at December 31, 2014	-125,485
Fair value at December 31, 2014	$6,780

Reconciliation_of_Federal_Stat

(Reconciliation of Federal Statutory Income Tax Provision To Company's Actual Provision) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Benefit at federal statutory tax rate	($2,222,000)	($1,647,000)
Foreign rate differential	159,000	141,330
UK Energy Incentives	-649,000	0
Unbenefited operating losses	2,062,960	1,505,670
Provision for income taxes	4,000	13,450
Income tax provision	($645,040)	$13,450

Income_taxes_Schedule_of_Defer

Income taxes (Schedule of Deferred Tax Assets) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$10,838,000	$9,902,000
Accrued expenses and other	100,000	200,000
Stock compensation	1,194,000	1,014,000
Depreciation	-216,000	-516,000
Deferred tax assets and liabilties, net, before valuation allowance	11,916,000	10,600,000
Valuation allowance	-11,916,000	-10,600,000
Net deferred tax asset	$0	$0

Income_taxes_Details

Income taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Operating Loss Carryforwards [Line Items]
Increase in valuation allowance	$1,316,000	$1,511,000
Excess stock compensation deductions related to the amount of tax deductions on restricted stock in excess of book compensation expense	1,353,000
UK Energy Incentives	649,000	0
Federal
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	24,683,000
State
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	19,865,000
Foreign
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$3,595,000

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (USD $)	1 Months Ended	12 Months Ended
	Jul. 31, 2012	Dec. 31, 2014	Jun. 30, 2013
			sqft
			office
Commitments and Contingencies Disclosure [Abstract]
Support Services Agreement, Service Period	1 year
Related Party Agreement, Original Square Feet			3,071
Related Party Agreement, Square Feet			3,282
Related Party Agreement, Original Number of Offices			6
Related Party Agreement, Number of Offices			9
Rental Income Related Party		$6,495
Related Party Agreement, Period for Notice Termination	60 days

Subsequent_events_Details

Subsequent events (Details)	0 Months Ended
	Jan. 29, 2015	Dec. 31, 2014	25-May-14	Dec. 31, 2013	Nov. 25, 2013	25-May-13
Subsequent Event [Line Items]
Common stock, shares issued		52,140,001	260,154	49,817,920	377,391	316,462
IN Holdings Corp | Subsequent Event
Subsequent Event [Line Items]
Ownership Percentage in Company	5.00%
Number of entity's shares repurchased	1,320,000
IN Holdings Corp | Eurosite Power Inc | Subsequent Event
Subsequent Event [Line Items]
Common stock, shares issued	1,320,000

Uncategorized_Items

Uncategorized Items
[us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest]	37,001,439	48,491	983,535	-24,456,845