Item 8.01. Other Events. On January 14, 2025, Tecogen Inc. (the “ Company”) agreed to permit Mr. Earl R. Lewis, III, a director and shareholder of the Company, to convert the balance of the Company’s $500,000 promissory note dated September 18, 2024 in favor of Mr. Lewis (the “ Promissory Note”) to common stock of the Company at his request at any time he is not subject to restrictions on trading shares of the Company. If requested by Mr. Lewis, the balance of the Promissory Note will be converted to shares of the Company’s common stock by dividing the outstanding principal and accrued interest by the average closing price per share for the Company’s common stock during the thirty day period prior to the date of conversion of the loan balance to common stock. SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the Company has duly caused this report to be signed on its behalf by the undersigned, hereunto duly authorized. By: /s/ Abinand Rangesh Abinand Rangesh, Chief Executive Officer