The level of NPAs represents an indicator of the potential for future credit losses. NPAs consist of non-accrual loans and leases and other real estate owned. Changes in the level of non-accrual loans and leases typically represent increases for loans and leases that reach a specified past due status, offset by reductions for loans and leases that are charged-off, paid down, sold, transferred to held for sale classification, transferred to other real estate owned or are no longer classified as non-accrual because they have returned to accrual status as a result of continued performance and an improvement in the borrower’s financial condition and loan repayment capabilities.
Total NPAs were $17.6 million as of September 30, 2020, an increase of $11.8 million from December 31, 2019. The ratio of our NPAs to total loans and leases and other real estate owned was 0.13% as of September 30, 2020, an increase of 9 basis points from December 31, 2019. The increase in total NPAs was primarily due to a $7.0 million increase in commercial real estate non-accrual loans, a $2.4 million increase in residential mortgage non-accrual loans and a $2.0 million increase in construction non-accrual loans.
As of September 30, 2020, commercial real estate non-accrual loans were $7.1 million, an increase of $7.0 million from December 31, 2019. This increase was primarily due to additions of $15.9 million in commercial real estate loans, partially offset by transfers to loans held for sale of $5.3 million and $2.7 million in charge-offs. The additions in commercial real estate non-accruals loans during the year was primarily due to the impact of COVID-19 and the shut-down of the tourism industry in Hawaii.
As of September 30, 2020, commercial and industrial non-accrual loans were $0.7 million, an increase of $0.7 million from December 31, 2019. This increase was primarily due to additions in commercial and industrial loans totaling $28.6 million, partially offset by transfers to loans held for sale of $9.3 million, $13.4 million in charge-offs and $5.3 million in payments. The additions in commercial and industrial non-accruals loans during the year was primarily due to the impact of COVID-19 and the shut-down of the tourism industry in Hawaii.
As of September 30, 2020, construction non-accrual loans were $2.0 million, an increase of $2.0 million or 100% from December 31, 2019. This increase was primarily due to the addition of one construction non-accrual loan of $2.2 million, partially offset by a $0.4 million charge-off.
As of September 30, 2020, residential mortgage non-accrual loans were $7.8 million, an increase of $2.4 million or 44% from December 31, 2019. As of September 30, 2020, our residential mortgage non-accrual loans were comprised of 41 loans with a weighted average current LTV ratio of 55%.
Other real estate owned represents property acquired as the result of borrower defaults on loans. Other real estate owned is recorded at fair value, less estimated selling costs, at the time of foreclosure. On an ongoing basis, properties are appraised as required by market conditions and applicable regulations. As of September 30, 2020, there were no other real estate owned. As of December 31, 2019, other real estate owned was $0.3 million which was comprised of two residential real estate properties.
Loans and Leases Past Due 90 Days or More and Still Accruing Interest. Loans and leases in this category are 90 days or more past due, as to principal or interest, and are still accruing interest because they are well secured and in the process of collection.
Loans and leases past due 90 days or more and still accruing interest were $10.7 million as of September 30, 2020, a decrease of $1.4 million or 12% as compared to December 31, 2019. Construction and consumer loans that were past due 90 days or more and still accruing interest decreased by $2.3 million and $1.4 million, respectively, during the nine months ended September 30, 2020. This was partially offset by increases of $1.5 million and $0.5 million in home equity lines and commercial and industrial loans, respectively, that were past due 90 days or more and still accruing interest during the nine months ended September 30, 2020.
Impaired Loans. A loan is impaired when, based on current information and events, it is probable that a creditor will be unable to collect all amounts due according to the contractual terms of the loan agreement. For a loan that has been modified in a TDR, the contractual terms of the loan agreement refers to the contractual terms specified by the original loan agreement, not the contractual terms specified by the modified loan agreement.