| Cover | Jul. 24, 2023 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Aug. 09, 2023 |
| Entity Registrant Name | TECOGEN INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-36103 |
| Entity Tax Identification Number | 04-3536131 |
| Entity Address, Address Line One | 45 First Avenue |
| Entity Address, State or Province | MA |
| Entity Address, City or Town | Waltham |
| Entity Address, Postal Zip Code | 02451 |
| City Area Code | 781 |
| Local Phone Number | 466-6400 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
| Entity Central Index Key | 0001537435 |
