Item 2.02. Results of Operations and Financial Condition. On May 12, 2025, Tecogen Inc. (the “ Company”) issued a press release with earnings commentary and supplemental information for the three months ended March 31, 2025. A copy of the press release is attached as Exhibit 99.1 to this Current report on Form 8-K. The information in this Item 2.02 and Exhibit 99.01 to this Current Report on Form 8-K shall shall not be deemed “filed” for purposes of Section 18 of the Exchange Act or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act or the Exchange Act, except as expressly set forth by specific reference in such a filing.

Item 7.01. Regulation FD Disclosure. On May 13, 2024, the registrant will present the attached slides online in connection with an earnings conference call. The slides are being furnished as Exhibit 99.2 to this Current Report on Form 8-K. The information in this Item 7.01 and Exhibit 99.2 to this Current Report on Form 8-K shall not be deemed “filed” for purposes of Section 18 of the Exchange Act or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act or the Exchange Act, except as expressly set forth by specific reference in such a filing.

Item 9.01. Financial Statements and Exhibits. (d) Exhibits Exhibit Description 99.1 Tecogen Earnings Release dated May 12, 2025 for the three months ended March 31, 2025 99.2 Tecogen Earnings Call Presentation dated May 13, 2025 ────────────────────────────────────────────────────────────────────────────────────────────────────── 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. TECOGEN INC. By: /s/ Abinand Rangesh May 12, 2025 Abinand Rangesh, Chief Executive Officer