TECOGEN INC.

Management’s Evaluation of Disclosure Controls and Procedures:

Our disclosure controls and procedures are designed to provide reasonable assurance that the control system’s objectives will be met. Our management, including our Chief Executive Officer and Chief Financial Officer, after evaluating the effectiveness of our disclosure controls and procedures as of December 31, 2025 ("Evaluation Date"), has concluded that as of the Evaluation Date, our disclosure controls and procedures were not effective due to a material weakness in financial reporting relating to a small number of employees dealing with general controls over information technology. Our management has decided that the expense associated with continued implementation of new systems is justified and continues to implement systems to put the proper control procedures in place to remediate this weakness.

For these purposes, the term disclosure controls and procedures of an issuer means controls and other procedures of an issuer that are designed to ensure that information required to be disclosed by the issuer in the reports that it files or submits under Section 13(a) or 15(d) of the Securities Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by an issuer in the reports that it files or submits under Section 13(a) or 15(d) of the Securities Exchange Act is accumulated and communicated to the issuer’s management, including its principal executive and principal accounting officers, or persons performing similar functions, as appropriate to allow timely decisions regarding required disclosure.

Management’s Annual Report on Internal Control over Financial Reporting:

Our management is responsible for establishing and maintaining adequate internal controls over financial reporting as defined in Rules 13a-15(f) under the Securities Exchange Act of 1934, as amended.

Our internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles in the United States. Our internal controls over financial reporting includes those policies and procedures that:

•pertain to the maintenance of records that in reasonable detail accurately and fairly reflect the transactions and dispositions of the assets of the Company;

•provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with U.S. generally accepted accounting principles, and that receipts and expenditures of the Company are being made only in accordance with authorizations of management and directors of the Company; and

•provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the Company’s assets that could have a material effect on the consolidated financial statements.

Because of its inherent limitations, internal control over financial reporting, no matter how well designed, may not prevent or detect misstatements. Accordingly, even effective internal control over financial reporting can provide only reasonable assurance with respect to financial statement preparation. Also, the assessment of the effectiveness of internal control over financial reporting was made as of a specific date. Projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Management, including our Chief Executive Officer and Chief Financial Officer, conducted an evaluation of our internal control over financial reporting based on the framework and criteria established in Internal Control—Integrated Framework, issued by the Committee of Sponsoring Organizations of the Treadway Commission. This evaluation included review of the documentation of controls, evaluation of the design effectiveness of controls, testing of the operating effectiveness of controls and a conclusion regarding this evaluation. Due to the small number of employees dealing with general controls over information technology security and user access, management believes this constitutes a material weakness in financial reporting. Based on this evaluation, management concluded that our internal control over financial reporting was not effective as of December 31, 2025.

Our management, including our Chief Executive Officer and Chief Financial Officer, does not expect that our disclosure controls or our internal control over financial reporting will prevent or detect all errors and all fraud. A control system, no matter how well designed and operated, can provide only reasonable, not absolute, assurance that the control system’s objectives will be met. The design of a control system must reflect the fact that there are resource constraints, and the benefits of controls must be considered relative to their costs. Further, because of the inherent limitations in all control systems, no evaluation of controls can provide absolute assurance that misstatements due to error or fraud will not occur or that all control issues and instances of fraud, if any, within the Company have been detected. These inherent limitations include the realities that judgments in decision-making can be faulty and that breakdowns can occur because of a simple error or mistake. Controls can also be circumvented by the individual acts of some persons, by collusion of two or more people, or by management override of the controls. The design of any system of controls is based in part on certain assumptions about the likelihood of future events, and there can be no assurance that any design will succeed in achieving its stated goals under all potential future conditions.

This annual report does not include an attestation report of our registered independent public accounting firm regarding internal control over financial reporting. Management’s report was not subject to attestation by our registered independent public accounting firm pursuant to rules of the Securities and Exchange Commission that permit us to provide only management’s report in this Annual Report on Form 10-K.

Remediation

We are committed to remediating the material weakness identified in internal controls over financial reporting and have begun the process to remediate this material weakness. Our efforts have focused on instituting mitigating controls to address segregation of duties; hiring of additional staff; implementing additional controls to address system access deficiencies; implementing additional controls over business operations; establish independent review and verification procedures for our vendor and customer master files; enhance the documentation to support review occurrences and approval procedures; and, commence regular periodic reviews of our internal controls over financial reporting with our Board of Directors and Audit Committee to address the inadequate risk oversight function and institute procedures to evaluate and report on risks to financial reporting, including the documentation and completion of a comprehensive risk assessment to identify all potential risk areas and evaluate the adequacy of our controls to mitigate these risks.

Changes in Internal Control Over Financial Reporting

During the year ended December 31, 2025, we implemented system access controls to address system access deficiencies and have instituted mitigating controls to address segregation of duty issues. In addition, we have implemented mitigating controls throughout our financial reporting process, allowing us to address the insufficient segregation of duties, oversight of work performed and allow us to continue to institute additional compensating or mitigating controls and will also allow us to document internal control support occurrences and approval procedures. We have instituted systems access controls and mitigating controls to system access. There are no other changes that have materially affected or are reasonably likely to materially affect our internal controls over financial reporting (as such term is defined in Rules 13a-15(f) and 15d-15(f) under the Securities Exchange Act).