TGEN Tecogen Inc. - 10-K

Item 1A. Risk Factors

Our business operations, financial condition, results of operations and stock price may be affected by a number of factors. In addition to the other information in this Annual Report on Form 10-K, the following factors and the information contained under the heading ''Cautionary Note Concerning Forward-Looking Statements'' should be considered in evaluating our company and our business. The risks described below may not be the only risks we face. Additional risks that we do not yet know of, or that we currently think are immaterial, may also impair our business operations or financial results. If any of the events or circumstances described in the following risk factors occur, our business, financial condition and results of operations could suffer and the trading price of our common stock could decline.

Risks Relating to Our Business and Financial Condition

Our operating history is characterized by net losses. There can be no assurance we will be able to increase our revenues and become profitable in the future.

We have historically incurred net losses, including net loss of $8,248,755 in 2025 and a net loss of $4,760,238 in 2024. We have an accumulated deficit as of December 31, 2025 of $55,888,649 and working capital of $19,618,132. Our business is capital intensive and, because our products generally are built to order with customized configurations, the lead time to build and deliver a unit can be significant. We may be required to purchase key components long before we can deliver a unit and receive payment. Changes in customer orders or lack of demand may also impact our profitability. There can be no assurance we will be able to increase our sales and achieve and sustain profitability in the future.

We are dependent on a limited number of third-party suppliers for the supply of key components for our products.

We use third-party suppliers for components in all of our products. Our engines and generators required in our cogeneration products (other than the InVerde), and the compressor and vessel sets in our chillers, are all purchased from large multinational equipment manufacturers. The loss of one or more of our suppliers could materially and adversely affect our business if we are unable to replace them. While alternate suppliers for the manufacture of our engine, generators and compressors have been identified should the need arise, there can be no assurance that alternate suppliers will be available and able to provide such items on acceptable terms or on a timely basis.

From time to time, shipments of components for our products can be delayed because of industry-wide or other shortages of necessary materials and components from third-party suppliers, as well as shipping delays at points of importation. A supplier's failure to supply components in a timely manner, or to supply components that meet our quality, quantity, or cost requirements, or our inability to obtain substitute sources of these components on a timely basis or on terms acceptable to us, could impair our ability to deliver our products in accordance with contractual obligations.

We depend on a small number of customers for a substantial portion of our product revenues. The loss of one or more of these customers, or our inability to collect outstanding receivables from such customers could have a material adverse effect on our financial results.

Although we are seeking to increase and diversify our customer base and reduce our reliance upon sales to a small number of customers, we expect sales to such customers to continue to constitute a significant portion of our revenues in the near term because we actively pursue large contracts and projects. The loss of any one or more of such customers or an inability to collect resulting accounts receivables could have a material adverse effect our business, financial condition and results of operations.

For the year ended December 31, 2025 one customer represented more than 10% of our revenue. No customer represented more than 10% of our revenue for the year ended December 31, 2024. One customer represented 11% of our accounts receivable balance as of December 31, 2025, and one customer represented 14% of our accounts receivable balance as of December 31, 2024. The loss of any one or more of our major customers or our inability to collect outstanding accounts receivable from one or more of these customers could have a material adverse effect on our business and financial condition. Our provision for credit losses decreased to $62,958 in the year ended December 31, 2025, compared to $146,010 in the year ended December 31, 2024, due to the write down of certain install receivables which were deemed uncollectible in the year ended December 31, 2024. Our allowance for credit losses increased $93,147 to $389,079 in the year ended December 31, 2025, compared to the year ended December 31, 2024.

The amount of our backlog is subject to fluctuation due to our customers’ experiencing unexpected delays in financing, permitting, or modifications in specifications of the equipment.

Our backlog as of December 31, 2025 was $2,522,231 compared to $12,336,248 as of December 31, 2024. Our backlog at December 31, 2024 included an order for several chillers which were shipped in 2025 and orders for our several cogeneration systems that shipped in the first quarter of 2025 to customers seeking tax credits under the Inflation Reduction Act of 2022. Although we expect our customers to issue definitive purchase orders with respect to such backlog, there can be no

TECOGEN INC.

assurance that such amounts will not be subject to modification in the event customers experience unexpected delays in obtaining permits, interconnection agreements, or financing. We have experienced order delays and deferrals for our products due to business closures or the inability to obtain government issued permits to conduct product installations. Any of such events may result in customers modifying the equipment or the terms or timing of the expected installation, which may result in changes to the amount of backlog attributed to those projects.

We experience significant fluctuations in revenues and product mix from quarter to quarter on our product sales which may make period to period comparisons difficult.

We have low volume, high dollar sales for projects that are generally non-recurring, and therefore our sales have fluctuated significantly from period to period. Fluctuations cannot be predicted because they are affected by the purchasing decisions and timing requirements of our customers, which are unpredictable. Such fluctuations may make quarter to quarter and year to year comparisons difficult.

We expect significant competition for our products and services.

Many of our competitors and potential competitors are well established and have substantially greater financial, research and development, technical, manufacturing, and marketing resources than we do. If these larger competitors decide to focus on the development of distributed power or cogeneration, they have the manufacturing, marketing, and sales capabilities to complete research, development, and commercialization of these products more quickly and effectively than we can. There can also be no assurance that current and future competitors will not develop new or enhanced technologies or more cost-effective systems, and therefore, there can be no assurance that we will be successful in this competitive environment.

We may not achieve production cost reductions necessary to competitively price our products, which would adversely affect our sales.

We may need to reduce the unit production cost of our products over time to maintain our ability to offer competitively priced products. Our ability to achieve cost reductions will depend on our ability to develop low-cost design enhancements, to obtain necessary tooling and favorable supplier contracts, and to increase sales volumes so we can achieve economies of scale. We can make no assurance that we will be able to achieve any such production cost reductions. Our failure to do so could have a material adverse effect on our business and results of operations.

Our products involve a lengthy sales cycle and we may not anticipate sales levels appropriately, which could impair our results of operations.

The sale of our products typically involves a significant commitment of capital by customers, with the attendant delays frequently associated with large capital expenditures. For these and other reasons, the sales cycle associated with our products is typically lengthy and subject to a number of significant risks over which we have little or no control. We plan our production and inventory levels based on internal forecasts of customer demand, which is highly unpredictable and can fluctuate substantially. If sales in any period fall significantly below anticipated levels, our financial condition, results of operations and cash flow would suffer. If demand in any period increases well above anticipated levels, we may have difficulties in responding, incur greater costs to respond, or be unable to fulfill the demand in sufficient time to retain the order, which would negatively impact our operations. In addition, our operating expenses are based on anticipated sales levels, and a high percentage of our expenses are generally fixed in the short term. As a result of these factors, a small fluctuation in timing of sales can cause operating results to vary materially from period to period.

The economic viability of our projects depends on the price spread between natural gas and other fuel and electricity, and the variability of these prices creates a risk that our projects will not be economically viable and that potential customers will avoid such energy price risks.

The economic viability of our CHP products depends on the spread between natural gas fuel and electricity prices. Volatility in one component of the spread, such as the cost of natural gas and other fuels (e.g., propane or distillate oil), can be managed to some extent by means of futures contracts. However, the regional rates charged for both base load and peak electricity may decline periodically due to excess generating capacity or general economic recessions, and both the cost of natural gas and the cost of electricity for base load and peak load may be adversely affected by market forces and geopolitical disruptions such as Russian expansion into the Ukraine and the conflict in the Middle East and political and other responses to such activity.

Our products and on-site utility service could become less competitive if electric rates were to fall substantially in the future, although, historically, electric rates have not experienced any sustained decline in price. Potential customers may perceive the risk of unpredictable swings in natural gas and electricity prices as a risk of investing in on-site CHP, and may decide not to purchase CHP products.

TECOGEN INC.

We may make acquisitions or take other corporate strategic actions that could harm our financial performance.

To expedite the development of our business, including with regard to equipment installation and service functions, we anticipate investigating and potentially pursuing future acquisitions of complementary businesses, and may engage in discussions with respect to possible acquisitions, sale of assets, business combinations, and joint ventures intended to complement or expand our business, some of which may be significant transactions for us. Regardless of whether we consummate any such transaction, the negotiation of a potential transaction could require us to incur significant costs, including as a result of professional fees and due diligence efforts, and cause diversion of management’s time and resources. In addition, we may be unable to identify suitable acquisition or strategic investment opportunities or may be unable to obtain any required financing or regulatory approvals and therefore may be unable to complete such acquisitions or strategic investments on favorable terms, if at all. We may decide to pursue acquisitions with which our investors may not agree, and we cannot assure investors that any acquisition or investment will be successful or otherwise provide a favorable return on investment. In addition, acquisitions and the integration thereof require significant time and resources and place significant demands on our management, as well as on our operational and financial infrastructure. If we fail to successfully close transactions or integrate new teams, or integrate the products and technologies associated with these acquisitions into our company, our business could be seriously harmed. In addition, acquisitions may expose us to operational challenges and risks, including:

• the ability to profitably manage acquired businesses or successfully integrate the acquired businesses’ operations, personnel, financial reporting, accounting and internal controls, technologies and products into the our business;

• increased indebtedness and the expense of integrating acquired businesses, including significant administrative, operational, economic, geographic or cultural challenges in managing and integrating the expanded or combined operations;

• entry into jurisdictions or acquisition of products or technologies with which we have limited or no prior experience, and the potential of increased competition with new or existing competitors as a result of such acquisitions;

• diversion of management’s attention and the over-extension of our operating infrastructure and our management systems, information technology systems, and internal controls and procedures, which may be inadequate to support growth;

• the ability to fund our capital needs and any cash flow shortages that may occur if anticipated revenue is not realized or is delayed, whether by general economic or market conditions, or unforeseen internal difficulties; and

• the ability to retain or hire qualified personnel required for expanded operations.

Our acquisition strategy may not succeed if we are unable to remain attractive to target companies or expeditiously close transactions. Issuing securities to fund an acquisition would cause dilution to existing shareholders. If we develop a reputation for being a difficult acquirer or target companies view our shares unfavorably, we may be unable to consummate key acquisition transactions essential to our corporate strategy and our business may be seriously harmed.

In addition, integrating any business that we acquire may be distracting to our management and disruptive to our business and may result in significant costs to us. We could face several challenges in the consolidation and integration of information technology, accounting systems, personnel and operations. Any such transaction could also result in the impairment of goodwill and other intangibles, development write-offs and other related expenses. Any of the foregoing could have a material adverse effect on our business, financial condition, operating results, liquidity and prospects.

Expiring customer contracts may lead to decreases in revenue and increases in expenses.

Each year, a portion of our customer contracts expire and need to be renewed or replaced. We may not be able to renew or extend contracts with existing customers or obtain replacement contracts at attractive rates or for the same term as the expiring contracts. To the extent we are unable to extend customer contracts prior to their expiration dates, energy production revenue will decline due to decreased billing for maintenance services and energy production. Expiring customer contracts can also lead to an increase in expenses because we are obligated to remove the equipment from the customer location at our own expense at the end of the customer contract. The investment required to obtain replacement contracts, including the manufacture and installation of the cogeneration or chiller equipment and the costs to incorporate this equipment into a facility are significant. To the extent that we do not have sufficient liquidity, our ability to add new contracts with energy production sites may be adversely impacted.

Our revenue from energy billing may be adversely impacted by increases in the price of natural gas, reductions in utility rates for electrical power, weather conditions, or by an increase in remote work and study environments, all of which could reduce our revenue.

TECOGEN INC.

Over the past several years electric rates have fluctuated, and in some instances rates have decreased, subsequent to customer contract dates, causing the billable value of the electrical power generated by our systems to decrease which has an adverse effect on our results of operations. In warmer months the customers do not use as much thermal energy because they do not have as much demand for heat at their locations. Due to lower demand in warmer months, our revenue from thermal energy billing during those periods. In addition, increases in the cost of natural gas may increase the cost of power generation in comparison to the cost of power from the electric grid, and may result in decreased revenue and adversely affect our results of operation.

We may be affected by global climate change or by legal, regulatory, or market responses to such change.

The growing political and scientific sentiment is that global weather patterns are being influenced by increased levels of greenhouse gases in the earth’s atmosphere. This growing sentiment and the concern over climate change have led to legislative and regulatory initiatives aimed at reducing greenhouse gas emissions which warm the earth’s atmosphere. These warmer weather conditions could result in a decrease in demand for our products in general. Moreover, proposals that would impose mandatory requirements on greenhouse gas emissions continue to be considered by policy makers in the United States. Laws enacted that could impact demand for the products we sell could adversely affect our business, financial condition, results of operations and cash flows. Significant increases in federal, state or municipal restrictions on emissions of carbon dioxide that may be imposed on gas-driven cogeneration and chillers could adversely affect demand for our product. Our inability to respond to such changes could adversely impact the demand for our products and our business, financial condition, results of operations or cash flows.

Our financial condition and results of operations could suffer if there is an impairment of goodwill or intangible assets.

We are required to test intangible assets with indefinite lives, including goodwill, annually or, in certain instances, more frequently, and may be required to record impairment charges, which would reduce any earnings or increase any loss for the period in which the impairment was determined to have occurred. Our goodwill impairment analysis is sensitive to changes in key assumptions used in our analysis. If the assumptions used in our analysis are not realized, it is possible that an impairment charge may need to be recorded in the future. We cannot accurately predict the amount and timing of any impairment of goodwill or other intangible assets. However, any such impairment would have an adverse effect on our results of operations.

As of December 31, 2025, our goodwill was $1,248,442, and our intangible assets were $2,146,503. We performed a goodwill impairment test at December 31, 2025, and determined that the carrying value of our energy production business assets exceeded the estimated fair value of the energy production business assets based on a discounted cash flow analysis, and we recognized goodwill and long-lived asset impairment relating to our energy production and product segments of $1,098,124 for the year ended December 31, 2025. The fair value of the Aegis maintenance service contracts based on a discounted cash flow analysis exceeded the carrying value of the assets, and we did not recognize goodwill impairment relating to our services segment for the year ended December 31, 2025.

Increased costs of labor and employee health and welfare benefits may impact our results of operations.

Labor is a primary component in the cost of operating our business. Increased labor costs, due to competition, inflationary pressures, increased federal, state, local or foreign minimum wage requirements and increased employee benefit costs, including health care costs and social security benefits, could adversely impact our operating expenses. Because payroll costs are a major component of the operating expenses, a shortage of skilled labor could require higher wages that would increase labor costs, which could adversely affect our results of operations and cash flows.

We are dependent on the continued contributions of our senior management and other key employees, and the loss of any of whom could adversely affect our business, operating results, and financial condition.

Our future performance depends on the continued contributions of our senior management, including our Chief Executive Officer, Abinand Rangesh, our President and Chief Operating Officer, Robert Panora, our Chief Financial Officer, Roger Deschenes, and other key employees, to execute on our business plan, develop new products and services, source new customers, and enter into new partnerships. In addition, our success, in part, depends on our ability to attract and retain qualified member of our board and our board committees. The failure to properly manage succession plans or the loss of services of senior management, other key employees or members of our board could significantly delay or prevent the achievement of our strategic objectives. From time to time, there may be changes in our senior management team resulting from the hiring or departure of executives, which could disrupt our business. We do not currently maintain key person life insurance policies on any of our employees. The loss of the services of one or more of our senior management or other key employees for any reason could adversely affect our business, financial condition, and operating results, and require significant amounts of time, training, and resources to recruit suitable replacements and integrate them within our business and could affect our corporate culture.

TECOGEN INC.

Risks Related to Our Technologies

If we are unable to maintain our technological expertise in design and manufacturing processes, we will not be able to successfully compete.

We believe that our future success will depend upon our ability to continue to develop and provide innovative products and product enhancements that meet the increasingly sophisticated needs of our customers. However, this requires that we successfully anticipate and respond to technological changes in design and manufacturing processes in a cost-effective and timely manner. The development of new, technologically advanced products and enhancements is a complex and uncertain process requiring high levels of innovation, as well as the accurate anticipation of technological and market trends. There can be no assurance that we will successfully identify new product opportunities, develop and bring new or enhanced products to market in a timely manner, successfully lower costs, and achieve market acceptance of our products, or that products and technologies developed by others will not render our products or technologies obsolete or noncompetitive.

The introduction of products embodying new technologies and the shifting of customer demands or changing industry standards could render our existing products obsolete and unmarketable. We may experience delays in releasing new products and product enhancements in the future. Material delays in introducing new products or product enhancements may cause customers to forego purchases of our products and purchase products offered by our competitors.

Legal, Regulatory and Compliance Risks

Our business is subject to product liability and warranty claims.

Our business exposes us to potential product liability claims, which are inherent in the manufacturing, marketing and sale of our products, and we may face substantial liability for damages resulting from the faulty design, manufacture, or improper use of products by end users. We currently maintain product liability insurance, but there can be no assurance that this insurance will provide sufficient coverage in the event of a claim. Also, we cannot predict whether we will be able to maintain such coverage on acceptable terms, if at all, or that a product liability claim would not harm our business or financial condition. In addition, negative publicity in connection with the faulty design or manufacture of our products would adversely affect our ability to market and sell our products.

We sell our products with limited warranties. There can be no assurance that the provision in our financial statements for estimated product warranty expense will be sufficient. There can be no assurance that our efforts to reduce our risk through warranty disclaimers will effectively limit our liability. Any significant occurrence of warranty expense in excess of estimates could have a material adverse effect on our operating results, financial condition and cash flow. Further, we have at times undertaken programs to enhance the performance of units previously sold. These enhancements have at times been provided at no cost or below our cost. If we offer such programs in the future, such actions could result in significant costs.

Changes in regulations applicable to our businesses may impair the profitability of our businesses, and our failure to comply with applicable laws and regulations may increase our costs, reduce our earnings or limit our growth.

We may be required to incur costs to comply with regulatory requirements, such as those relating to employment practices, environmental requirements, and other regulatory matters, and the costs of compliance, investigation, remediation, litigation, and resolution of regulatory matters could be substantial. We are subject to extensive federal and state employment laws and regulations, including wage and hour laws and other pay practices and employee record-keeping requirements. We may periodically have to defend against lawsuits asserting non-compliance. Such lawsuits can be costly, time consuming and distract management, and adverse rulings in these types of claims could negatively affect our businesses, financial condition or results.

In addition, we are subject to audit or review by federal or state regulatory authorities as a result of applying for and obtaining a Paycheck Protection Program loan pursuant to the Coronavirus Aid, Relief and Economic Security Act, and for obtaining forgiveness of the loan. If we were to be audited or reviewed and receive an adverse determination or finding in such an audit or review, we could be required to return or repay the full amount of the applicable loan and could be subject to fines or penalties, which could reduce our liquidity and adversely affect our business, financial condition and results of operations.

Changes in any of these regulations or regulatory activities in any of these areas, or others, may require us to spend additional amounts to comply with the regulations, or may restrict our ability to offer products and services in ways that are profitable.

Agreements with our customers may include potential liquidated damages relating to construction delays or performance guaranties.

Construction contracts involving our products may contain liquidated damages provisions resulting from failure to achieve agreed milestones relating to construction activity. Agreements relating to the sale of equipment or energy may include performance and other obligations that may result in payment obligations to customers.

TECOGEN INC.

Utilities or governmental entities could hinder our entry into and growth in the marketplace, and we may not be able to effectively sell our products.

Utilities or governmental entities on occasion have placed barriers to the installation of our products or their interconnection with the electric grid, and they may continue to do so. Utilities may charge additional fees to customers who install on-site CHP and rely on the grid for back-up power. These types of restrictions, fees, or charges could make it harder for customers to install our products or use them effectively, as well as increase costs to potential customers. This could make our systems less desirable, thereby adversely affecting our revenue and other operating results.

The reduction, elimination or expiration of government and economic incentives for applications of our equipment could reduce demand for our equipment and harm our business.

The market for cogeneration equipment depends in part on the availability and size of government and economic incentives that vary by geographic market. Because our sales to customers are typically into geographic areas with such incentives, elimination, or expiration of government subsidies and economic incentives for cogeneration equipment may negatively affect the competitiveness of our equipment relative to other sources of electricity, heating, and cooling equipment, and could harm or halt the growth of the cogeneration industry and our business.

We may incorporate price reductions on equipment sold to customers based on the anticipated receipt of governmental economic incentive payments and apply and collect the incentives payments. If such incentives become unavailable to us our financial condition may be adversely affected.

Competing sources of electricity, heating, and cooling equipment may successfully lobby for changes in the relevant legislation in their markets that are harmful to the cogeneration industry. Reductions in, or eliminations or expirations of, governmental incentives in regions where we focus our sales efforts could result in decreased demand for and lower revenue from cogeneration equipment there, which would adversely affect us. In addition, our ability to successfully penetrate new geographic markets may depend on new geographic areas adopting and maintaining incentives to promote cogeneration, to the extent such incentives are not currently in place. Additionally, electric utility companies may establish pricing structures or interconnection requirements that could adversely affect our sales and be harmful to cogeneration.

We may be exposed to substantial liability claims if we fail to fulfill our obligations to our customers or our on-site equipment malfunctions.

We enter into contracts with large commercial and not-for-profit customers under which we assume responsibility for meeting a portion of the customers' building energy demand and equipment installation. We may be exposed to substantial liability claims if we fail to fulfill our obligations to such customers. If the equipment malfunctions, it may be costly to repair or replace. There can be no assurance that we will not be vulnerable to claims by customers and by third parties that are beyond any contractual protections that we are able to negotiate. As a result, liability claims could cause us significant financial harm.

Losses or unauthorized access to or releases of confidential information, including personal information, could subject us to significant reputational, financial, legal and operational consequences.

Our business requires us to use and store confidential information, including personal information, with respect to our customers and employees and also requires us to share confidential information with suppliers and other third parties. We rely on suppliers that are also exposed to ransomware and other malicious attacks that can disrupt business operations. Although we take steps to secure confidential information that is provided to or accessible by third parties working on our behalf, such measures may not always be effective and losses or unauthorized access to or releases of confidential information may occur. Such incidents and other malicious attacks could materially adversely affect our business, reputation, results of operations and financial condition.

We have implemented systems and processes intended to secure our information technology systems and prevent unauthorized access to or loss of sensitive data, and mitigate the impact of unauthorized access, including through the use of encryption and authentication technologies and we continue to undertake regular reviews of our IT infrastructure and have investigated improved software and hardware cyber threat protection solutions. These measures cannot provide absolute security, and losses or unauthorized access to or releases of confidential information may occur and could materially adversely affect our business, reputation, results of operations and financial condition.

We have experienced malicious attacks and other attempts to gain unauthorized access to our systems, including the ransomware attack on our computer network which occurred on April 28, 2023 which required that we limit user access, remove the hard drives from two affected workstations from service and restore network files from systems backups. Our network returned to full operation on May 1, 2023. Since this incident, we have implemented changes to user access passwords, conducted a full audit of user accounts and implemented multi-factor authentication for network and workstation access. These attacks seek to compromise the confidentiality, integrity or availability of confidential information, or disrupt normal business operations, and could, among other things, impair our ability to attract and retain customers for our products and services, impact our stock price, materially damage commercial relationships, and expose us to litigation or government investigations,

TECOGEN INC.

which could result in penalties, fines, or judgments against us. Globally, attacks are expected to continue accelerating in both frequency and sophistication with increasing use by actors of tools and techniques that are designed to circumvent controls, avoid detection, and remove or obfuscate forensic evidence, all of which hinders our ability to identify, investigate and recover from incidents.

Credit and Liquidity Risks

We are exposed to credit risks with respect to some of our customers.

To the extent our customers do not advance us sufficient funds to finance our costs during the execution phase of our contracts, we are exposed to the risk that they may be unable to accept delivery or that they will be unable to make payment at the time of delivery or within agreed upon payment terms. We have experienced customer payment delays due to COVID-19, which are attributable to temporary business shutdowns, resulting in declines in revenues and cash flows from our customers and delays in project completion due to delays in government project inspections and a general slowdown in business activity and in some cases, customers ceasing business activities altogether.

Our provision for credit losses decreased to $62,958 in the year ended December 31, 2025, compared to $146,010 in the year ended December 31, 2024, due to the write down of certain install receivables which were deemed uncollectible in the year ended December 31, 2024. Our allowance for credit losses was $389,079 as of December 31, 2025, an increase of $93,147 when compared to the allowance for credit losses as of December 31, 2024.

Risks Relating to Ownership of our Common Stock

Investment in our Common Stock is subject to price fluctuations and market volatility.

Historically, valuations of many small companies have been highly volatile. The securities of many small companies have experienced significant price and trading volume fluctuations unrelated to the operating performance or the prospects of such companies. The market price of shares of our common stock could be subject to wide fluctuations in response to many risk factors listed in this section, and others beyond our control, including:

• results and timing of our product development;

• results of the development of our competitors’ products;

• regulatory actions with respect to our products or our competitors’ products;

• actual or anticipated fluctuations in our financial condition and operating results;

• actual or anticipated changes in our growth rate relative to our competitors;

• actual or anticipated fluctuations in our competitors’ operating results or changes in their growth rate;

• competition from existing products or new products that may emerge;

• announcements by us or our competitors of significant acquisitions, strategic partnerships, joint ventures, collaborations, or capital commitments;

• issuance of new or updated research or reports by securities analysts;

• fluctuations in the valuation of companies perceived by investors to be comparable to us;

• share price and volume fluctuations attributable to inconsistent trading volume levels of our shares;

• additions or departures of key management or personnel;

• disputes or other developments related to proprietary rights, including patents, litigation matters, and our ability to obtain, maintain, defend or enforce proprietary rights relating to our products and technologies;

• announcement or expectation of additional financing efforts;

• sales of our shares by us, our insiders, or our other stockholders;

• political events, war, terrorism, public health issues, natural disasters and other circumstances;

• lawsuits threatened or filed against us; and

• general economic and market conditions.

Furthermore, the U.S. stock markets have experienced extreme price and volume fluctuations that have affected and continue to affect the market prices of equity securities of many companies. These fluctuations often have been unrelated or disproportionate to the operating performance of those companies. These broad market and industry fluctuations, as well as

TECOGEN INC.

general economic, political, and market conditions such as recessions, interest rate changes, or international currency fluctuations may negatively impact the market price of shares of our common stock. In addition, such fluctuations could subject us to securities class action litigation, which could result in substantial costs and divert our management’s attention from other business concerns, which could potentially harm our business.

Additionally, selling short is a technique used by a stockholder to take advantage of an anticipated decline in the price of a security. A significant number of short sales or a large volume of other sales within a relatively short period of time can create downward pressure on the market price of a security. Holders of our securities could, therefore, experience a decline in the value of their investment as a result of short sales or a high volume of selling of our shares.

If securities or industry analysts do not publish research or publish inaccurate or unfavorable research about our business, our share price and trading volume could decline.

The trading market for our shares will depend on the research and reports that securities or industry analysts publish about us or our business. There can be no assurance that analysts will cover us or provide favorable coverage. If one or more analysts downgrade our shares or change their opinion of our share price our share price may decline. In addition, if one or more analysts cease coverage of us or fails to regularly publish reports on us, we could lose visibility in the financial markets, which could cause our share price or trading volume to decline.

Because our directors and executive officers are among our largest stockholders, they can exert influence over our business and affairs and have actual or potential interests that may differ from other stockholders or investors.

As of the date of this report, our directors and executive officers and related parties directly, indirectly, and through trusts for the benefit of family members, collectively beneficially own approximately 37.7% of our issued and outstanding shares. Additionally, the holdings of our directors and executive officers may increase in the future upon vesting or exercise of the options or other stock awards they may hold or in the future may be granted or if they otherwise acquire additional shares in the open market or otherwise. The interests of such persons may differ from the interests of our other stockholders. As a result, in addition to their board seats and offices, such persons will have influence over corporate actions requiring shareholder approval. These matters would include the election of directors and the approval of mergers or other business combination transactions. Such persons’ stock ownership may discourage a potential acquirer from making a tender offer or otherwise attempting to acquire us, which in turn could reduce our stock price or prevent our stockholders from realizing a premium over our stock price.

Current stock holdings may be diluted if we make future equity issuances or if outstanding options are exercised for shares of our common stock.

“Dilution” refers to the reduction in the voting effect and proportionate ownership interest of a given number of shares of common stock as the total number of shares increases. Our issuance of additional common stock, preferred stock, or convertible debt may result in dilution to the interests of shareholders and may also result in the reduction of our stock price. The sale of a substantial number of shares into the market, or even the perception that sales could occur, could depress the price of our common stock. Also, the exercise of options may result in additional dilution.

The holders of outstanding options, warrants and convertible securities or derivatives, if any, have the opportunity to profit from a rise in the market price of our shares, if any, without assuming the risk of ownership, with a resulting dilution in the interests of other stockholders. We may find it more difficult to raise additional equity capital if it should be needed for our business while options, warrants, or convertible securities are outstanding.

Future sales of our shares by our existing stockholders may cause our stock price to fall.

The market price of our shares could decline as a result of sales by our existing stockholders of our shares in the market or the perception that these sales could occur. These sales might also make it more difficult for us to conduct an equity or equity-based financing at a time and price that we deem appropriate and thus inhibit our ability to raise additional capital when it is needed.

Because we have not and do not intend to pay cash dividends, our stockholders receive no current income from holding our stock.

We have paid no cash dividends on our capital stock to date, and we currently intend to retain our future earnings, if any, to fund the operation and expansion of our business, and therefore do not anticipate paying any cash dividends in the foreseeable future. As a result, capital appreciation, if any, of our common stock could be the sole source of gain for our stockholders for the foreseeable future.

We incur substantial costs to operate as a public reporting company.

We incur substantial legal, financial, accounting and other costs and expenses to operate as a public reporting company. We believe that these costs are a disproportionately larger percentage of our revenues than they are for many larger companies. In addition, the rules and regulations of the SEC impose significant requirements on public companies, including

TECOGEN INC.

ongoing disclosure obligations and mandatory corporate governance practices. Our senior management and other personnel need to devote a substantial amount of time to ensure ongoing compliance with these requirements. Our common stock is currently listed on the NYSE American LLC ("NYSE American") stock exchange. On May 6, 2025, our common stock began trading on the NYSE American under our current symbol "TGEN." Also, we must be current in our SEC reporting obligations to maintain our listing. There can be no assurance that we will continue to meet all of the public company requirements to which we are subject on a timely basis, or at all, or that our compliance costs will not continue to be material.

As a public reporting company, we are subject to rules and regulations established from time to time by the SEC and Public Company Accounting Oversight Board (“PCAOB”) regarding our disclosure controls and internal controls over financial reporting. If we fail to establish and maintain effective disclosure controls and procedures and internal controls over financial reporting, we may not be able to accurately report our financial results or report them in a timely manner. Investor confidence in the price of our stock may be adversely affected if we are unable to comply with such rules and regulations.

As a public reporting company under the Securities Exchange Act, we are subject to the rules and regulations established from time to time by the SEC and the PCAOB. These rules and regulations require, among other things, that we maintain disclosure controls and procedures and internal controls over financial reporting. In addition, as a public company we are required to document and test our internal control over financial reporting pursuant to Section 404 of the Sarbanes-Oxley Act of 2002 (“Sarbanes-Oxley Act”) so that our management can certify as to the effectiveness of our internal control over financial reporting.

Our Chief Executive Officer and Chief Financial Officer (“certifying officers”) are responsible for establishing and maintaining our disclosure controls and procedures (as defined in Securities Exchange Act Rule 13a-15(e) and Rule15d-15(e)). Our certifying officers designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under their supervision, to ensure that information required to be disclosed by us in the reports we file or submit under the Securities Exchange Act is recorded, processed, summarized and reported, within the time periods specified by the SEC’s rules and forms, and is made known to management (including the certifying officer) by others within the company, including our subsidiaries. We regularly evaluate the effectiveness of our disclosure controls and procedures and report our conclusions about the effectiveness of the disclosure controls quarterly in our Quarterly Reports on Form 10-Q and annually in our Annual Reports on Form 10-K. In completing such reporting, we will disclose, as appropriate, any significant change in our internal control over financial reporting that occurred during our most recent fiscal period that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.

Also, as a public company, we are subject to rules adopted by the SEC pursuant to Section 404 of the Sarbanes-Oxley Act, which require us to include in our annual report on Form 10-K our management’s report on, and assessment of the effectiveness of, our internal control over financial reporting (“management’s report”). If we fail to achieve and maintain the adequacy of our internal controls over financial reporting, there is a risk that we will not comply with all of the requirements imposed by Section 404. Moreover, effective internal control over financial reporting, particularly that relate to revenue recognition, is necessary for us to produce reliable financial reports and is important in helping to prevent financial fraud. Any of these possible outcomes could result in an adverse reaction in the financial marketplace due to a loss in investor confidence in the reliability of our financial statements, which ultimately could harm our business and could negatively impact on the market price of our common stock. Investor confidence and the price of our common stock may be adversely affected if we are unable to comply with Section 404 of the Sarbanes-Oxley Act.

As of the end of the period covered by our Annual Report on Form 10-K for the year ended December 31, 2025, our principal executive officer and principal financial officer have concluded that there is a material weakness in our disclosure controls and procedures and our internal control over financial reporting. If we are unable to remediate these material weaknesses, if management identifies additional material weaknesses in the future, or if we otherwise fail to maintain effective internal controls over financial reporting, we may not be able to accurately or timely report our financial position or results of operations, which may adversely affect our business and stock price or cause our access to the capital markets to be impaired.

As of the end of the period covered by our Annual Report on Form 10-K for the year ended December 31, 2025, our certifying officers performed an evaluation of our disclosure controls and procedures and concluded that our controls were not effective to provide reasonable assurance that information required to be disclosed by us in reports that we file under the Securities Exchange Act, is recorded, processed, summarized and reported when required. Our management, including our certifying officers, after evaluating the effectiveness of our disclosure controls and procedures, concluded that our disclosure controls and procedures were not effective as of December 31, 2025, due to material weakness with respect to a small number of individuals dealing with general controls over information technology. Any failure to implement effective internal controls could harm our operating results or cause us to fail to meet our reporting obligations. Inadequate internal controls could also

TECOGEN INC.

cause investors to lose confidence in our reported financial information, which could have a negative effect on the trading price of our common stock and may require us to incur additional costs to improve our internal control system.

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 will focus 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; establishing independent review and verification procedures for our vendor and customer master files; enhancing the documentation to support review occurrences and approval procedures; and, commencing 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.

In addition, on March 11, 2025, we filed a Current Report on Form 8-K to report, among other things, certain changes in the level of compensation for Mr. Panora, our President and COO, and the resignation of Mr. Gehret, our Vice President of Operations. Although Mr. Gehret remained with us as an employee until February 28, 2025, and then as a consultant until his duties were transferred to Mr. Panora, and subsequently determined we did not report Mr. Gehret’s resignation timely in accordance with the requirements of Form 8-K.

We continue to develop and refine our disclosure controls and other procedures. We are continuing to improve our internal control over financial reporting which may require us to hire additional accounting and financial personnel to implement such processes and controls and to provide additional training to our existing personnel. We expect to incur costs related to implementing our internal compliance function to further improve our internal control environment.

If we identify further deficiencies in our internal control over financial reporting in the future or if we are unable to comply with the demands placed upon us as a public company, including the requirements of Section 404 of the Sarbanes-Oxley Act, in a timely manner, we may be unable to accurately report our financial results, or report them within the timeframes required by the SEC. We also could become subject to regulatory action. In addition, if we are unable to assert that our internal controls over financial reporting are effective, investors may lose confidence in the accuracy and completeness of our financial reports, we may face restricted access to the capital markets, and our stock price may be adversely affected.

Our current controls and any new controls that we develop may become inadequate because of changes in our business, and weaknesses in our disclosure controls and procedures and internal control over financial reporting may be discovered in the future. Any failure to develop or maintain effective controls or any difficulties encountered in their implementation or improvement could cause us to fail to meet our reporting obligations, result in a restatement of our financial statements for prior periods, undermine investor confidence in us, and adversely affect the trading price of our common stock. Our disclosure controls and procedures are designed to provide reasonable assurance that the control system's objectives will be met.

We are a “smaller reporting company” within the meaning of the Securities Act and Securities Exchange Act and we intend to take advantage of certain exemptions from disclosure requirements available to smaller reporting companies which could make our securities less attractive to investors and may make it more difficult to compare our performance with that of other public companies.

We are a “smaller reporting company” as defined in Item 10(f)(1) of Regulation S-K. Smaller reporting companies may take advantage of certain reduced disclosure obligations, including, among other things, providing only two years of audited financial statements. We will remain a smaller reporting company until the last day of the fiscal year in which (i) the market value of the shares of common stock held by non-affiliates exceeds $250 million as of the prior June 30, and (ii) our annual revenue exceeded $100 million during such completed fiscal year or the market value of the shares of common stock held by non-affiliates exceeds $700 million as of the prior June 30. To the extent we take advantage of such reduced disclosure obligations, it may also make comparison of our financial statements with other public companies difficult or impossible.

Delaware law and our certificate of incorporation and bylaws contain certain provisions, including anti-takeover provisions that limit the ability of stockholders to take certain actions and could delay or discourage takeover attempts that stockholders may consider favorable.

Our certificate of incorporation, bylaws and the Delaware General Corporations Law (“DGCL”) contain provisions that could have the effect of rendering more difficult, delaying or preventing an acquisition that stockholders may consider favorable, including transactions in which stockholders might otherwise receive a premium for their shares. These provisions could also limit the price that investors might be willing to pay in the future for shares of our common stock and therefore depress the trading price. These provisions could also make it difficult for stockholders to take certain actions, including electing directors who are not nominated by the incumbent members of the board of directors or taking other corporate actions,

TECOGEN INC.

including effecting changes in our management. Among other things, our certificate of incorporation bylaws, or DGCL include provisions that:

• permit the board to issue shares of preferred stock, including “blank check” preferred stock and to determine the price and other terms of those shares, including preferences and voting rights, without stockholder approval, which could be used to significantly dilute the ownership of a hostile acquire

• prohibit cumulative voting in the election of directors, which limits the ability of minority stockholders to elect director candidates

• limit the liability of, and provide for the indemnification of, our directors and officers

• permit the board to amend our bylaws, which may allow the board to take additional actions to prevent an unsolicited takeover and inhibit the ability of an acquirer to amend the bylaws to facilitate an unsolicited takeover attempt

• require a supermajority vote of stockholders to amend certain provisions of our certificate of incorporation and a supermajority vote of stockholders in order to amend our bylaws

• limit our ability to engage in business combinations with certain interested stockholders without certain approvals

• permit only the board, the chief executive officer of the company or the chairperson of the board to call special stockholder meetings;

• mandate advance notice procedures with which stockholders must comply in order to nominate candidates to the board or to propose matters to be acted upon at a stockholders’ meeting, which could preclude stockholders from bringing matters before annual or special meetings of stockholders and delay changes in the board and also may discourage or deter a potential acquirer from conducting a solicitation of proxies to elect the acquirer’s own slate of directors or otherwise attempting to obtain control of our company, and

• provide that directors may be removed only for cause and only by a supermajority vote of our stockholders

These provisions, alone or together, could delay or prevent hostile takeovers and changes in control or changes in our board or management.

General Business Risks

Our intellectual property may not be adequately protected.

We seek to protect our intellectual property rights through patents, trademarks, copyrights, trade secret laws, confidentiality agreements, and licensing arrangements, but we cannot ensure that we will be able to adequately protect our technology from misappropriation or infringement. We cannot ensure that our existing intellectual property rights will not be invalidated, circumvented, challenged, or rendered unenforceable.

Our competitors may successfully challenge the validity of our patents, design non-infringing products, or deliberately infringe our patents. There can be no assurance that other companies are not investigating or developing other similar technologies. In addition, our intellectual property rights may not provide a competitive advantage to us or ensure that our products and technology will be adequately covered by our patents and other intellectual property. Any of these factors or the expiration, termination, or invalidity of one or more of our patents may have a material adverse effect on our business.

Others may assert that our technology infringes their intellectual property rights.

We may be subject to infringement claims from time to time. The defense of any claims of infringement made against us by third parties could involve significant legal costs and require our management to divert time from our business operations. If we are unsuccessful in defending any claims of infringement, we may be forced to obtain licenses or to pay additional royalties to continue to use our technology. We may not be able to obtain any necessary licenses on commercially reasonable terms or at all. If we fail to obtain necessary licenses or other rights, or if these licenses are costly, our operating results would suffer either from reductions in revenues through our inability to serve customers or from increases in costs to license third-party technologies.

Our business and financial performance may be adversely affected by information systems interruptions, cybersecurity attacks or other disruptions which could have a material adverse effect on our business and results from operations.

We depend upon information technology, infrastructure, including network, hardware and software systems to conduct our business. Despite our implementation of security measures, there are numerous and evolving risks to cybersecurity and privacy, including risks originating from intentional acts of criminal hackers, nation states and competitors, intentional and unintentional acts or omissions of customers, vendors, contractors, employees and other third parties that may result in damage,

TECOGEN INC.

breakdown, or interruption from computer viruses, ransomware, malware, phishing, social engineering, fraudulent inducement, electronic fraud, wire fraud, human error or malfeasance, unauthorized access, natural disasters, and telecommunications and electrical failures. We directly or indirectly store, collect and transmit sensitive data, including intellectual property, confidential information, proprietary business information, and customer or personal data. The secure processing of such data, maintenance, and transmission of such data is important to our operations. We face increased cybersecurity risks due to our reliance on internet technology, among other things, to monitor our installed products or systems remotely. We may not be able to anticipate all types of security threats or be able to implement security measures effective against all such threats or implement preventive measures effective against all such threats. The techniques used by cybercriminals change frequently and may not be recognized until launched and can originate from a wide variety of sources. Even if identified, we may not be able to adequately investigate or remediate incidents or breaches due to attacks increasingly using tools and techniques that are designed to circumvent controls, to avoid detection, and to remove or obfuscate forensic evidence. Accordingly, our data protection efforts and related security measures may not be adequate to protect against highly targeted sophisticated cyber-attacks, or other improper disclosures of confidential and/or sensitive information. Additionally, we may have access to confidential or other sensitive information of our customers or suppliers, which despite our efforts to protect, may be vulnerable to security breaches, theft, or improper disclosure, any of which could have a material adverse effect on our competitive position, results of operations, cash flows, or financial condition. The increase in personnel working remotely during and after the Covid-19 pandemic has increased the risk of our and our vendors and suppliers’ security breaches and incidents. If a security breach or other incident results in unauthorized access to, or use, disclosure, release, or other processing of confidential or proprietary information, we could incur liability, and it may be necessary to notify persons, governmental authorities, supervisory bodies, the media and other parties pursuant to privacy and security laws. Any such access, disclosure or other loss of information could result in legal claims, proceedings, liability under laws that protect the privacy of personal information of our employees or others, and any such event could disrupt our operations, damage our reputation, and cause a loss of confidence in us. Our contracts with our customers and suppliers may not contain limitation of liability and there can be no assurance that limitations of liability in our contracts are sufficient to protect us from liabilities, damages, or claims related to privacy, data protection, or data security. Further, we can give no assurance that our insurance coverage will be adequate or sufficient to cover the financial, legal, business or reputational losses that may result from an interruption or breach of our systems, that such coverage will continue to be available on commercially reasonable terms or at all, or that such coverage will pay future claims.

Our success is dependent upon attracting and retaining highly qualified personnel and the loss of key personnel could significantly hurt our business.

To achieve success, we must attract and retain highly qualified technical, operational and executive employees. The loss of the services of key employees or an inability to attract, train and retain qualified and skilled employees, specifically engineering, operations, and business development personnel, could result in the loss of business or could otherwise negatively impact on our ability to operate and grow our business successfully.

Our business may be impacted by political events, war, terrorism, public health issues, natural disasters and other circumstances that are not within our control.

War, terrorism, geopolitical uncertainties, public health issues, and other business interruptions have caused and could cause damage or disruption to international commerce and the global economy, and thus could have a material adverse effect on us, our suppliers, and manufacturing vendors. Our business operations are subject to interruption by natural disasters, fire, power shortages, nuclear power plant accidents, terrorist attacks, and other hostile acts, labor disputes, public health issues, and other events beyond our control. Such events could decrease demand for our products, make it difficult or impossible for us to make and deliver products to our customers, or to receive products from our manufacturers and suppliers, and create delays and inefficiencies in our supply chain. If major public health issues, including pandemics, arise, we could be adversely affected by more stringent employee travel restrictions, limitations in freight services, governmental actions limiting the movement of products between regions, delays in production ramps of new products, and disruptions in the operations of our manufacturing vendors and suppliers. In the event of such issues, we could incur significant losses, require substantial recovery time and experience significant expenditures in order to resume operations.

We may be subject to litigation, including securities class action litigation, which may harm our business and operating results.

Our share price may be volatile and in the past companies that have experienced volatility in the market price of their stock have been subject to an increased incidence of securities class action litigation. Securities litigation against us could result in substantial costs and damages and divert our management’s attention from other business concerns, which could seriously harm our business, results of operations, financial condition or cash flows.

TECOGEN INC.

Although we maintain directors’ and officers’ insurance coverage, there can be no assurances that this insurance coverage will be sufficient to cover the substantial fees and expenses of lawyers and other professional advisors relating to any future litigation, our obligations to indemnify our officers and directors who are or may become parties to such pending and future actions, or the amount of any judgments or settlements that we may be obligated to pay in connection with such actions. We may be required to make material payments in connection with the defense of or to settle such litigation or to satisfy any adverse judgment. In addition, actions that arise in the future could be excluded from coverage or, if covered, could exceed our deductibles and/or the coverage provided. In addition, an adverse outcome in any such litigation could cause our insurance premiums and retention amounts to increase in the future. Any of these consequences could have a material adverse effect on our business, financial condition and results of operations. For more information regarding litigation, see "Item 3. Legal Proceedings" and Note 12 "Commitments and Contingencies" in the Notes to our Consolidated Financial Statements included elsewhere herein.

We may also be called on to defend against lawsuits relating to our business operations. Some of these claims may seek significant damages amounts. Due to the inherent uncertainties of litigation, the ultimate outcome of any such proceedings cannot be accurately predicted. A future unfavorable outcome in a legal proceeding could have an adverse impact on our business, financial condition and results of operations.

In addition, current and future litigation, regardless of its merits, could result in substantial legal fees, settlements or judgment costs and a diversion of our management’s attention and resources that are needed to successfully run our business.

Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations.

The following discussion and analysis and other parts of this report should be read in conjunction with our audited consolidated financial statements and the accompanying notes thereto included in this report and is qualified in its entirety by the foregoing and by more detailed financial information appearing elsewhere in this report. In addition to historical financial information, the following discussion and analysis contains forward-looking statements that involve risks, uncertainties and assumptions. You should review the “Risk Factors” in this report for a discussion of important factors that could cause actual results to differ materially from the results described in or implied by the forward-looking statements contained in the following discussion and analysis. While we may elect to update forward-looking statements in the future, except as required by law, we specifically disclaim any obligation to do so, even if our estimates change, and you should not rely on those forward-looking statements as representing our views as of any date subsequent to the date of the filing of this report. Our historical results are not necessarily indicative of the results that may be expected for any period in the future.

Overview

Tecogen designs, manufactures, markets, and maintains high efficiency, ultra-clean cogeneration products. These include natural gas engine driven combined heat and power (CHP) systems, chillers and heat pumps for multi-family residential, commercial, recreational and industrial use. We are known for products that provide customers with substantial energy savings, resiliency from utility power outages and for significantly reducing a customer’s carbon footprint. Our products are sold with our patented Ultera technology which nearly eliminates all criteria pollutants such as NOx and CO. Our systems are greater than 88% efficient compared to typical electrical grid efficiencies of 40% to 50%. As a result, our greenhouse gas (GHG) emissions are typically half that of the electrical grid. Our systems generate electricity and hot water or in the case of our Tecochill product, both chilled water and hot water. These result in savings of energy related costs of up to 60% for our customers. Our products are expected to run on Renewable Natural Gas (RNG) as it is introduced into the US gas pipeline infrastructure.

Our products are sold directly to end-users by our in-house sales team and by established sales agents and representatives. We have agreements in place with distributors and sales representatives. Our existing customers include hospitals and nursing homes, colleges and universities, health clubs and spas, hotels and motels, office and retail buildings, food and beverage processors, multi-unit residential buildings, laundries, ice rinks, swimming pools, factories, municipal buildings, military installations and indoor growing facilities. To date we have shipped over 3,200 units, some of which have been operating for almost 35 years.

Although we may, from time to time, have one or a few customers who may represent more than 10% of our product revenue for a given year, we are not dependent on the recurrence of revenue from those customers. Our product revenue is such that customers may make a large purchase once and may not ever make a purchase again. Our equipment is built to last 30 or more years. Therefore, our product revenue model is not dependent on recurring sales transactions from the same customer. Our service revenue does lend itself to recurring revenue from particular customers.

For the last two fiscal years, more than half of our revenue was generated from long-term maintenance and energy production contracts, which provides us with a predictable revenue stream, especially during the summer months. We experience a slight surge of activity from May through September as our “chiller season” is in full swing. Our O&M service

TECOGEN INC.

Table of Contents

revenue which has grown from year to year since 2005, with our New York City/New Jersey and New England systems experiencing the majority of the growth, was positively impacted by the Aegis maintenance agreement acquisition in 2023. Our installation service related revenue has decreased and is likely to continue to remain low due to our strategy to focus on higher margin segments of our business. Our service margins are generally predictable as we service hundreds of long-term contracts with relatively low dollar, high volume sales.

During the years ended December 31, 2025 and 2024, our revenues were negatively impacted due to supply chain issues, customer order delays or deferrals and, service delays due to customer facility closures.

Our product revenue is derived from the sale of the various cogeneration modules, such as the InVerde, InVerde e+, the Tecopower, and Tecochill products. In 2019, we also reintroduced our TecoFrost refrigeration line. The sales cycle varies between 6 months to a year or more. Therefore, our product revenue can be difficult to predict and the expected margin can vary. In most cases we work with consulting engineers who specify our product in new and retrofit applications.

Our cogeneration, heat pump, and chiller modules are built to order and revenue is recognized upon shipment. The lead time to build and deliver a unit depends on its customized configuration and is approximately 12 to 14 weeks for a chiller and 6 to 8 weeks for a cogeneration system or heat pump, from time of purchase order. As revenue is recognized upon shipment, our work-in-process is an important factor in understanding our financial condition in any given quarter.

Our operations are comprised of three business segments, as follows:

• Products segment - designs, manufactures and sells industrial and commercial cogeneration systems;

• Services segment - provides maintenance services for Tecogen supplied products at customer sites; and,

• Energy Production segment - sells energy in the form of electricity, heat, hot water, and cooling to our customers under long-term sales agreements.

Recent Developments

Recent Equity Financing

On July 21, 2025, we closed on the sale of an aggregate of 3,985,000 shares of common stock, $0.001 par value per share ("common stock"), including an additional 485,000 shares of common stock to cover over-allotments, at a price to the public of $5.00 per share (before deduction of underwriting discounts and commissions), in a firm commitment underwritten public offering pursuant to an underwriting agreement, dated July 18, 2025, between the Company and Roth Capital Partners, LLC, as sole underwriter and manager for the offering ("Offering"). The net proceeds from the Offering, after deducting underwriting discounts and commissions and offering expenses were approximately $18,105,100. See "Note 1. Description of Business and Basis of Presentation" of the Notes to Condensed Consolidated Statements for additional detail on the net Offering proceeds.

We have used and intend to use the net proceeds of the Offering for continued product development, increased sales and marketing activities, sales, marketing, additional human resources, capital expenditures, repayment of related party promissory notes and other costs and expenses we may incur in connection with the anticipated expansion into the data center market, and for general working capital and corporate purposes.

Uplist to NYSE American Stock Exchange

On April 30, 2025, we announced that our common stock had been approved for listing on the NYSE American LLC ("NYSE American") stock exchange. On May 6, 2025, our common stock began trading on the NYSE American under our current symbol "TGEN."

Vertiv Sales and Marketing Agreement - Data Center Cooling Market

On February 28, 2025, we entered into a Sales and Marketing Agreement with Vertiv Corporation (“Vertiv”) relating to sales of Tecogen DTx chillers for data center cooling applications (“Vertiv Agreement”). The Vertiv Agreement has a term of two years and provides that Vertiv will engage in establishing a budget for marketing activities and use commercially reasonable efforts to sell our DTx chillers for cooling applications in data centers. The Vertiv Agreement also provides the basis for the negotiation of a definitive supply agreement between us and Vertiv. We have agreed to provide Vertiv with reasonable discounts for purchases of significant volumes of our chillers, and Vertiv has agreed to use commercially reasonable efforts to assist us in securing favorable terms for engineering components and supplies for manufacturing our chillers. Pursuant to the Vertiv Agreement we have granted Vertiv the exclusive right to market and sell our DTx chillers for data center cooling applications outside the United States, and the non-exclusive right to market and sell our DTx chillers for such applications within the United States. We have also agreed to grant Vertiv the exclusive right to market and sell our DTx chillers for data center cooling applications in the United States if Vertiv achieves and maintains agreed sales levels of DTx chillers. The foregoing description of the Vertiv Agreement is not complete and is qualified in its entirety by reference to the full text

TECOGEN INC.

Table of Contents

thereof, a copy of which was filed as Exhibit 99.01 to our Current Report on Form 8-K filed with the Securities and Exchange Commission ("SEC") on February 28, 2025.

Assumption of Aegis Energy Services Maintenance Agreements

On March 15, 2023, we entered into an agreement ("Agreement") with Aegis Energy Services, LLC (“Aegis”) pursuant to which Aegis agreed to assign to us and we agreed to assume certain Aegis maintenance agreements, we agreed to purchase certain assets, and related matters (“Acquisition”). On April 1, 2023, the Acquisition closed. Under the Agreement, we agreed to acquire from Aegis and assume Aegis' rights and obligations arising on or after April 1, 2023 under maintenance agreements pursuant to which Aegis provided maintenance services for approximately 200 cogeneration systems, and acquired certain vehicles and inventory used by Aegis in connection with the performance of such maintenance services, and following closing, hired eight (8) Aegis employees to provide services with respect to such maintenance agreements. At closing, we acquired eight (8) Aegis vehicles for consideration consisting of $170,000 in cash. Also, we issued credits against outstanding accounts receivable due from Aegis in the amount of $300,000 for the acquisition of inventory that Aegis used to provide maintenance services.

On February 1, 2024, Tecogen and Aegis amended the Agreement to add eighteen (18) additional maintenance service agreements (the "First Amendment"). The First Amendment includes an undertaking by Aegis to use commercially reasonable efforts to support and assist our execution of maintenance service agreements for an additional thirty-six (36) cogeneration units sold to customers by Aegis.

On May 1, 2024, Tecogen and Aegis amended the Agreement to add thirty-one (31) additional maintenance contracts (the "Second Amendment"). The Second Amendment includes an undertaking by Aegis to use commercially reasonable efforts to support and assist our execution of maintenance service agreements for an additional forty-eight (48) cogeneration units sold to customers by Aegis.

See Note 5. "Aegis Contract and Related Asset Acquisition" of the Notes to the Consolidated Financial Statements.

Facilities Relocation

In April, 2024, we moved our manufacturing operations and corporate offices from 45 First Avenue, Waltham, Massachusetts to 76 Treble Cove Road, Building 1, North Billerica, Massachusetts. As a result of the relocation, product revenues were impacted during the second and third quarters of 2024. The factory relocation also necessitated construction activities to install equipment test cells and comply with local regulations. We resumed manufacturing operations during the latter-half of the third quarter of 2024.

Impact of Anti-fossil Fuel Sentiment

In some key markets such as New York City, the regulatory push to eliminate fossil fuels from buildings has impacted cogeneration unit sales. We believe that as regulations take into account scope 2 emissions and products like our hybrid chiller that can choose the cleanest fuel source will have a significant advantage in decarbonization efforts. The political environment following the 2024 elections in the United States has had a material impact on anti-fossil fuel sentiment and the regulatory environment that is more favorable to our business. We have also diversified our sales activities to reduce our reliance on markets like New York City.

Impact of Utility Power Constraints, Data Center Construction

As more load is added to the utility grid in the form of data centers, EV charging, and other demands for power, customers are facing power constraints. Tecogen believes that these power-constrained customers, in particular data centers and industrial facilities, represent a significant opportunity for growth. The customer need is driven by the ability to expand an existing facility or open a new facility quickly while taking advantage of utility expense savings long term. Our chiller products can reduce the electrical capacity needed on-site by 30% or more. Our InVerde product can provide on-site power generation which allows customers to eliminate long lead times associated with electrical switch gear and bridge any short fall in power from the utility.

Tecochill Hybrid-Drive Air-Cooled Chiller Development

During the third quarter of 2021, we began development of the Tecochill Hybrid-Drive Air-Cooled Chiller. We recognized that there were many applications where the customer wanted an easy to install chiller. Using the inverter design from our InVerde e+ cogeneration module, the system can simultaneously take two inputs, one from the grid or a renewable energy source and one from our natural gas engine. This allows a customer to seek the optimum blend of operational cost savings and greenhouse gas benefits while providing added resiliency from two power sources. We introduced the Tecochill Hybrid-Drive Air-Cooled Chiller at the AHR Expo in February 2023 and received an order on February 8, 2024 for three hybrid-drive air-cooled chillers for a utility company in Florida which were shipped in the second and third quarter of 2025. In

TECOGEN INC.

Table of Contents

March 2024, the US Patent and Trademark Office granted patent 11,936,327: "Hybrid Power System With Electric Generator and Auxiliary Power Source."

Impact of Geopolitical Tensions

We have no operations or customers in Russia, the Ukraine, or in the Middle East, including the recent military action in Iran. The higher energy prices for natural gas as a result of the war may affect the performance of our Energy Production Segment and the cost differential between grid generated energy and natural gas sourced energy using our cogeneration equipment. However, we have also seen higher electricity prices as much of the electricity production in the United States is generated from fossil fuels. If the electricity prices continue to rise, the economic savings generated by our products are likely to increase. In addition to the direct result of changes in natural gas and electricity prices, the war in Ukraine and the conflict in the Middle East may result in higher cybersecurity risks, increased or ongoing supply chain challenges, and volatility related to the trading prices of commodities.

Related Party Notes

On October 9, 2023, we entered into note subscription agreements with each of John N. Hatsopoulos and Earl R. Lewis, III, each a director and shareholder of the Company, pursuant to which Mr. Hatsopoulos agreed to provide financing to us of up to $1,000,000, and Mr. Lewis agreed to provide financing to us of $500,000, and potentially, an additional $500,000 at his discretion. On October 10, 2023, we borrowed $500,000 from Mr. Hatsopoulos and issued him a one-year promissory note with interest accruing at 5.12% per annum. On July 23, 2024, we borrowed an additional $500,000 from Mr. Hatsopoulos, and issued a one-year promissory note with interest accruing at 5.06% per annum. On March 21, 2024, we extended the maturity date the of the promissory note dated October 10, 2023 by one-year making the maturity date October 10, 2025. On September 18, 2024, we borrowed $500,000 from Mr. Lewis and issued him a one-year promissory note with interest accruing at 4.57% per annum.

On January 14, 2025, we agreed to permit Mr. Lewis to either receive repayment of his note in cash or, at his discretion, convert the balance of the promissory note into shares of our common stock. In the event of such a conversion, the number of shares we were required to be issue is determined by dividing the balance due under the promissory note by the average closing price per share of our shares during the thirty-day period prior to the date of conversion.

On February 18, 2025, we amended the promissory notes with Mr. Hatsopoulos to extend the maturity dates for both promissory notes to July 31, 2026. We also agreed to permit Mr. Hatsopoulos to either receive repayment of his notes in cash, or at his discretion, convert the balance(s) due of one or both of the promissory notes into shares of our common stock. In the event of such a conversion, the number of shares we were required to issue is determined by dividing the balance(s) due under the promissory note(s) by the average closing price per share of our shares during the thirty-day period prior to the date of conversion. Both of the promissory notes with Mr. Hatsopoulos were reclassified to long-term liabilities due to the February 18, 2025 amendment.

The promissory notes were repaid in full or converted to shares of our common stock in the year ended December 31, 2025. See Note 11."Related Party Notes" of the Notes to the Consolidated Financial Statements.

Critical Accounting Estimates

Our discussion and analysis of our financial condition and results of operations are based upon our consolidated financial statements, which have been prepared in accordance with accounting principles generally accepted in the United States. The preparation of these financial statements requires us to make judgments, assumptions and estimates that affect the reported amounts of assets, liabilities, sales and expenses, and related disclosure of contingent assets and liabilities. These judgments, assumptions and estimates are made or applied within the context of accounting policies related to the nature of the transaction. Note 2. "Summary of Significant Accounting Policies" of the Notes to our Consolidated Financial Statements describes the significant accounting policies used in the preparation of the consolidated financial statements.

Certain aspects of certain accounting policies require management to make difficult, subjective or complex judgments that could have a material effect on our financial condition and results of operations. These aspects of these accounting policies are considered critical accounting policies. These policies may require management to make assumptions about matters that are highly uncertain at the time of the estimate or employ an estimate where alternative estimates could have also been employed, and may involve estimates that are reasonably likely to change with the passage of time. Estimates and assumptions about future events and their effects cannot be determined with certainty.  We base our estimates on historical experience and on various other assumptions believed to be applicable and reasonable under the circumstances.  These estimates may change as new events occur, as additional information is obtained and as our operating environment changes.  These changes have historically been minor and have been included in the consolidated financial statements as soon as they became known.  In addition, management is periodically faced with uncertainties, the outcomes of which are not within its control and will not be known for prolonged periods of time.  These uncertainties are discussed in "Item 1A, Risk Factors" above.

TECOGEN INC.

Table of Contents

Management believes that the following are critical accounting estimates:

Revenue Recognition

Revenue is recognized when performance obligations under the terms of a contract with our customer are satisfied. This generally occurs with the transfer of control of our products, services and energy production. Revenue is measured as the amount of consideration we expect to receive in exchange for transferring goods or providing services or energy to customers.

Determination of contract consideration allocable to multiple performance obligations within a single contract requires employing stand-alone selling prices which may be based on observable selling prices, estimated selling prices or as a residual. We use an observable selling price to determine standalone selling prices where available and either a combination of an adjusted market assessment approach, an expected cost plus a margin approach, and/or a residual approach to determine the standalone selling prices for separate performance obligations as a basis for allocating contract consideration when an observable selling price is not available.

Accounts Receivable

Accounts receivable are stated at the amount management expects to collect from outstanding balances. The allowance for credit losses is estimated based on historical experience, aging of the receivable, the counterparty’s ability to pay, condition of the general economy and industry, and combined with management's estimate of current conditions, reasonable and supportable forecasts of future losses to determine estimated credit losses in our evaluation of outstanding accounts receivable at the end of the year. The allowance for credit losses reflects managements evaluation of our outstanding accounts receivable at the end of the year and our best estimate of probable losses inherent in the accounts receivable balance. Accounts receivable deemed uncollectible are charged against the allowance for credit losses when identified.

Inventory

Raw materials, work in process, and finished goods inventories are stated at the lower of cost, as determined by the average cost method, or net realizable value. We periodically review inventory quantities on hand for excess and/or obsolete inventory based primarily on historical usage, as well as based on estimated forecast of product demand. Any reserves that result from this review are charged to cost of sales.

Property, Plant and Equipment

Property, plant and equipment are recorded at cost. Depreciation is provided using the straight-line method over the estimated useful life of the asset, which range from three to fifteen years. Leasehold improvements are amortized using the straight-line method over the lesser of the estimated useful lives of the assets or the term of the related leases. Expenditures for maintenance and repairs are expensed, while renewals and betterments that materially extend the life of an asset are capitalized.

We review our property, plant and equipment for potential impairment whenever events or changes in business circumstances indicate that the carrying value of the assets may not be fully recoverable or that the useful lives of the assets are no longer appropriate. We evaluate the recoverability of our long-lived assets when impairment is indicated by comparing the net book value of the asset group to the estimated future undiscounted cash flows attributable to such assets. If the sum of the projected undiscounted cash flows (excluding interest charges) is less than the carrying value of the assets, the assets will be written down to the estimated fair value and such loss is recognized in income from continuing operations in the period in which the determination is made. If impairment is indicated, the asset is written down to its estimated fair value.

Business Combinations

In accordance with applicable accounting standards, we estimate the fair value of assets acquired and liabilities assumed as of the acquisition date of each business combination. Any excess purchase price over the fair value of the net tangible and intangible assets acquired is allocated to goodwill. We may make certain estimates and assumptions when determining the fair values of assets acquired and liabilities assumed, including intangible assets. Critical estimates in valuing certain intangible assets include but are not limited to future expected cash flows from energy production sites or customer maintenance contracts, estimated operating costs, as well as discount rates. At the acquisition date, we will also record acquisition related liabilities, if applicable, for any contingent consideration or deferred payments to the seller and pre-acquisition deferred maintenance contingencies identified at service contract acquisition. Contingent consideration and pre-acquisition deferred maintenance contingencies are recorded at fair value on the acquisition date based on our expectation of achieving the contractually defined revenue targets and actual and projected future costs. The fair value of the contingent consideration and pre-acquisition deferred maintenance liabilities are remeasured each reporting period after the acquisition date and any changes in the estimated fair value are reflected as gains or losses in cost of goods sold or general and administrative expense in the consolidated statement of operations. Contingent consideration liabilities and deferred payments to sellers are recorded as current liabilities and other long-term liabilities in the consolidated balance sheets based on the expected timing of settlement.

TECOGEN INC.

Table of Contents

Management’s estimates of fair value are based upon assumptions believed to be reasonable, but which are inherently uncertain and unpredictable and, as a result, actual results may differ from estimates. Any changes to provisional amounts identified during the measurement period are recognized in the reporting period in which the adjustment amounts are determined. Transaction costs associated with business combinations are expensed as incurred.

Contract Assets and Liabilities

The favorable contract asset and unfavorable contract liability included in the intangible assets and liabilities of the consolidated balance sheets represent the fair value of customer energy production contracts (both positive for favorable contracts and negative for unfavorable contracts) which were acquired by us.

The determination of fair value requires development of an estimate of the price at which an orderly transaction to sell the asset or to transfer the liability would take place between market participants at the measurement date under current market conditions. Contracts are considered to be assets or liabilities by virtue of the rights and obligations inherent in the contract terms. Typically, contracts with terms considered to be at market are considered to have no fair value as, in order to be entitled to the rights under the contract, performance must occur for which a market rate of return is earned due to the at market terms. The fair value of a contract is primarily a measurement of its off-market terms. The obligation to perform under a contract with terms that are unfavorable to market results in a liability to the extent its terms are off-market. The resulting liability is an estimate of the price that would need to be paid to a willing market participant to assume the obligations under the contract in order for them to receive a market rate of return for their remaining performance obligation under the contract. The opposite holds true in instances where the terms of a contract are considered to be favorable to market. In that case an asset would exist as an estimate of the price that would be received from a willing market participant in order to be entitled to the rights under the contract.

In determining the estimate of fair value of customer energy production contracts, the measure of market, and thus the baseline to measure the amount related to any of the off-market terms or conditions with respect to the contracts, was considered best determined, given the nature of the services provided under the contracts, by utilizing a benchmark level of margin, in this case 35% of revenue which is consistent with the average return on revenue of US investor owned public utilities.

Goodwill

Goodwill is not amortized; however, it is reviewed for impairment annually in the fourth quarter and/or when circumstances or other events indicate that impairment may have occurred. ASC 350 “Intangibles—Goodwill and Other” (ASC 350) permits entities to make a qualitative assessment of whether it is more likely than not that a reporting unit’s fair value is less than its carrying amount before applying the two-step goodwill impairment test. Circumstances that are considered as part of the qualitative assessment and could trigger the two-step impairment test include, but are not limited to: a significant adverse change in the business climate; a significant adverse legal judgment; adverse cash flow trends; an adverse action or assessment by a government agency; unanticipated competition; decline in our stock price; and a significant restructuring charge within a reporting unit. We define reporting units at the business segment level. For purposes of testing goodwill for impairment, goodwill has been allocated to our reporting units to the extent it relates to each reporting unit.

At a minimum, we perform a quantitative goodwill impairment test in the fourth quarter of the year. In the fourth quarter of 2025, we performed a quantitative goodwill impairment test for our energy production reporting unit acquired in 2017. We used a discounted cash flow approach to develop the estimated fair value of that reporting unit. Management judgment is required in developing the assumptions for the discounted cash flow model. An impairment would be recorded if the carrying amount of a reporting unit including goodwill exceeded the estimated fair value. Based on the aforementioned analysis, the carrying amount of that reporting unit, including goodwill, exceeded the estimated fair value and resulted in an impairment at December 31, 2025. See Note 6. "Sale of Energy Producing Assets".

The impairment analysis recognizes the shortening of remaining contract terms with customers without replacement and without further growth, as well as less than expected cost savings, offset by profitability from our initiatives to optimize the long-term profitability of our various site operations and a price peak of the our common stock on the date of the business combination to which the goodwill relates (see also Note 6."Sale of Energy Producing Assets").

The discount rate, profitability assumptions, and terminal growth rate of the Energy Production unit were the material assumptions utilized in the discounted cash flow model used to estimate its fair value. The discount rate reflects an estimate of our weighted-average cost of capital.

The discounted cash flow analysis requires estimates, assumptions and judgments about future events. Our analysis uses our internally generated long-range plan. The long-range plan reflects management's judgment and assumptions about future events.

TECOGEN INC.

Table of Contents

In the fourth quarter of 2025, we performed a quantitative goodwill impairment test for the Aegis maintenance service contracts reporting unit acquired in 2023 and 2024. We used a discounted cash flow approach to develop the estimated fair value of that reporting unit. Management judgment is required in developing the assumptions for the discounted cash flow model. An impairment would be recorded if the carrying amount of a reporting unit including goodwill exceeded the estimated fair value. Based on the aforementioned analysis, the estimated fair value of that reporting unit, including goodwill, exceeded the carrying value and resulted in no impairment at December 31, 2025. See Note 5. "Aegis Contract and Related Asset Acquisition".

The impairment analysis considers actual run hours and system uptime in forecasting future run hours and hourly billing rates, forecasted costs incurred to maintain the systems, assumes system downtime due to extensive repairs, contract attrition and assumes improvements in our service operations and system maintenance procedures to optimize the long-term profitability of the various maintenance service contracts.

The discount rate, profitability assumptions, and terminal growth rate of the Aegis Contract unit were the material assumptions utilized in the discounted cash flow model used to estimate its fair value. The discount rate reflects an estimate of our weighted-average cost of capital.

The discounted cash flow analysis requires estimates, assumptions and judgments about future events. Our analysis uses our internally generated long-range plan. The long-range plan reflects management's judgment and assumptions about future events.

We believe the assumptions used in our goodwill impairment analysis are appropriate and result in a reasonable estimate of the fair value of the reporting unit. However, due to uncertainties regarding the impact of the economic environment on our business, there can be no assurance that our estimates and assumptions, made for purposes of our goodwill impairment testing, will prove to be an accurate prediction of the future. If our assumptions regarding future performance are not achieved, we may be required to record additional goodwill impairment charges in future periods.

Results of Operations

Year Ended December 31, 2025 Compared to Year Ended December 31, 2024

The following table sets forth for the periods indicated, the percentages of the net sales represented by certain items reflected in our statements of operations for the years ended December 31, 2025 and 2024:

Years ended December 31,

Revenues

Cost of Sales

Gross Profit

Operating expenses:

General and administrative

Selling

Research and development

Loss (gain) on sale of assets

Goodwill impairment

Total operating expenses

Loss from operations

Total other expense, net

Consolidated net loss

Loss (income) attributable to the noncontrolling interest

Net loss attributable to Tecogen Inc.

TECOGEN INC.

Table of Contents

The following table presents revenue by segment and the change from the prior year for the years ended December 31, 2025 and 2024:

Years Ended

Revenues

December 31, 2025

December 31, 2024

Increase (Decrease) $

Increase (Decrease) %

Product:

Cogeneration

Chillers

Engineered Accessories

Total product revenue

Services

Energy production

Total Revenue

Revenues

Revenues in 2025 were $27,073,710 compared to $22,619,536 in 2024, an increase of $4,454,174 or 19.7% due to increased Products and Services revenues.

Products

Product revenues in 2025 were $9,133,450 compared to $4,443,996 in 2024, an increase of $4,689,454 or 105.5%. The increase in Products revenue in 2025 compared to 2024 is due to a $4,010,809 increase in chiller sales, $282,993 increase in engineered accessories sales and a $395,652 increase in cogeneration sales, due to increased unit volume. Our product mix, as well as product revenue, can vary significantly from period to period as our products are high dollar, low volume sales in which revenue is recognized upon shipment. The relocation to our new facility in April 2024 constrained our manufacturing capacity, which impacted product revenues during the second and third quarters of 2024.

Services

Revenues derived from our service centers in 2025 were $16,616,523 compared to $16,074,870 for the same period in 2024, an increase of $541,653 or 3.4%. The increase in Services revenue in 2025 is due to a $815,522, or 6.1% increase in service contract revenues from existing contracts, offset partially by a $273,869, or 10.3%, decrease in revenue from the acquired Aegis Maintenance contracts.

Our service operation revenues grow with the sales of installed systems, since the majority of our product sales are accompanied by a service contract or time and materials agreements. As a result, our “fleet” of units being serviced by our service department grows with product sales.

Energy Production

Energy production revenues for the year ended December 31, 2025 were $1,323,737 compared to $2,100,670 for 2024, a decrease of $776,933, or 37.0%. The decrease in Energy Production revenue for the year ended December 31, 2025 is due to the expiration of several energy production contracts in late 2024, decreased run hours at certain energy production sites due to temporary shutdowns for repairs and the guarantee shortfall of $84,854 recognized in 2025.

Cost of Sales

Cost of sales for the year ended December 31, 2025 was $17,249,202 compared to $12,749,363 in 2024, an increase of $4,499,839 or 35.3%. The increase in cost of sales is due to increased Products revenue volume and increased Services costs. Our overall gross margin was 36.3% in 2025 compared to 43.6% in 2024, a decrease of 7.3%. The decrease in gross margin for the year ended December 31, 2025 is due to the significant increase in our Services segment material and labor costs.

Products

Costs of sales for products the year ended December 31, 2025 was $6,097,501 compared to $3,014,655 in 2024, an increase of $3,082,846, or 102.3%, due to increased chillers Products revenue and increases in material and labor costs in 2025. Our products gross margin was 33.2% in 2025 compared to 32.2% in 2024, an increase of 1.0%, due to increased engineering accessories sales in 2025, which are higher margin sales.

Services

TECOGEN INC.

Table of Contents

Cost of sales for services for the year ended December 31, 2025 was $10,202,774 compared to $8,432,876 in 2024, an increase of $1,769,898, or 21.0%, due to increased labor and material costs as a consequence of acquiring the Aegis customer maintenance contracts and increased material usage at existing sites. Our services gross margin was 38.6% in 2025 compared to 47.5% in 2024, a decrease of 8.9%, due to increased labor and material costs incurred to replace engines at certain sites as we test improvements to our engine technology to improve engine performance, extend engine life and improved service margins.

Energy Production

Cost of sales for energy production for the year ended December 31, 2025 was $948,927 compared to $1,301,832 in 2024, a decrease of $352,905, of 27.1%. Energy production gross margin was 28.3% in 2025 compared to 38.0% in 2024, a decrease of 9.7%. The decrease in the energy production gross margin is due to lower revenue and increased repair costs incurred to restart energy production sites which were shut down for repairs during a portion of the year ended December 31, 2025, compared to the same period in 2024 and the guarantee shortfall of $84,854 recognized in 2025.

Operating Expenses

Operating expenses increased in 2025 to $18,069,338 compared to $14,404,260 in 2024, an increase of $3,665,078 or 25.4%.

Years Ended

Increase (Decrease)

December 31, 2025

December 31, 2024

Operating Expenses

General and administrative

Selling

Research and development

Loss (gain) on sale of assets

Goodwill impairment

Long-lived asset impairment

Total

General and administrative expenses increased $2,165,629, or 19.1%, to $13,522,035 in the year ended December 31, 2025 compared to $11,356,406 in 2024, due to a $490,192 increase in payroll and a $433,113 increase in employee benefits, a $264,638 increase in recruitment costs, a $274,191 increase in depreciation and amortization, a $224,331 increase in travel and vehicle expense, a $422,073 increase in freight costs, a $139,423 increase in stock-based compensation costs, a $123,049 increase in business insurance premiums, a $157,298 increase in operating supply costs, a $94,972 increase in filing fees and other taxes, offset partially by a $115,036 decrease in facility costs, due to the transition to our new facility in 2024, a $83,052 reduction in credit losses, due to the accounts receivable recovery of $75,000 recognized in 2025, a decrease in relocation costs of $83,055 incurred in 2024 and the $78,531 litigation provision reversal recognized in 2025.

Selling expenses increased in the year ended December 31, 2025 to $2,267,247 compared to $1,880,903 in 2024, an increase of $386,344, or 20.5%, due to a $296,573 increase in sales commissions on higher Products sales and a $70,439 increase in advertising and trade show expense targeted to the data center market..

Research and development expenses increased in the year ended December 31, 2025 to $1,166,744 compared to $961,837, an increase of $204,907 due to a $224,736 increase in payroll costs and related benefits, partially offset by a $14,800 decrease in outside consulting fees.

Loss on the sale of assets was $183 in 2025 compared to a gain on the sale of assets of $12,181 in 2024.

During the year ended December 31, 2025 we recognized goodwill and long-lived impairment of $1,113,129 on our Energy Production sites compared to $217,295 in 2024.

Loss from Operations

Loss from operations for the year ended December 31, 2025 was $8,244,830 compared to a loss of $4,534,087 in 2024, an increase in the loss from operations of $3,710,743, or 81.8%. The increase in the net loss from operations is due to an increase in operating expenses of $2,756,880, an increase in the goodwill and long-lived asset impairment of $895,834 and the decrease in Services segment gross margin.

Other Income (Expense), net

TECOGEN INC.

Table of Contents

Other income, net, for the year ended December 31, 2025 was $16,102 compared to other expense, net of $117,118 for the same period in 2024, an increase in income of $133,220, due to a $200,288 increase in interest income resulting from increased cash on deposit in interest-bearing accounts, offset by a $59,985 increase in interest expense on borrowings under our related party notes and lease financing and a $21,763 increase in currency exchange losses.

Provision for State Income Taxes

The provision for state income taxes for the years ended December 31, 2025 and 2024 were $20,615 and $22,565, respectively, and represents estimated income tax payments, net of refunds, to various states.

Noncontrolling Interest

We have income and losses attributable to the non-controlling interest we have in American DG Energy's 51% owned subsidiary, ADGNY, LLC. The non-controlling interest share of ADGNY profits and losses was a loss of $588 for the year ended December 31, 2025 compared to income of $86,468 in 2024. The decrease in the income attributable to the non-controlling interest in the year ended December 31, 2025, is due to the expiration of a contract at one of the Energy Production sites and the temporary shutdown of a site for repairs in 2025.

Net Loss Attributable to Tecogen Inc

Net loss for the year ended December 31, 2025 was $8,248,755 compared to a net loss of $4,760,238 for 2024, an increase of $3,488,517, or 73.3%. The increase in the net loss is due to an increase in operating expenses of $2,756,880, an increase in the goodwill and long-lived asset impairment of $895,834 and the decrease in Services segment gross margin, partially offset by increased interest income.

Net Income (Loss) Per Share

Net loss per share for the year ended December 31, 2025 was a loss of $0.30 compared to a loss of $0.19 per share for the same period in 2024. The basic and diluted weighted average shares outstanding for the year ended December 31, 2025 were 27,233,143 and 27,233,143, respectively. For the year ended December 31, 2024, basic and diluted shares weighted average shares outstanding were 24,861,190 and 24,861,190, respectively.

Liquidity and Capital Resources

Sources of Liquidity

During the year ended December 31, 2025, we incurred a loss from operations of $8,244,830 compared to a loss of $4,534,087 in the same period in 2024. For the year ended December 31, 2025 we used $9,911,674 in cash from operations compared to $4,060,547 in cash generated from operations in 2024, a decrease of $13,972,221 in net cash generated by operating activities. As of December 31, 2025, we had cash and cash equivalents of $12,430,287 compared to cash and cash equivalents of $5,405,233 as of December 31, 2024, an increase of $9,848,742 or 182.2%, and an accumulated deficit as of December 31, 2025, of $55,888,649.

Recent Equity Financing

On July 21, 2025, we closed on the sale of an aggregate of 3,985,000 shares of common stock, $0.001 par value per share ("common stock"), including an additional 485,000 shares of common stock to cover over-allotments, at a price to the public of $5.00 per share (before deduction of underwriting discounts and commissions), in a firm commitment underwritten public offering pursuant to an underwriting agreement, dated July 18, 2025, between the Company and Roth Capital Partners, LLC, as sole underwriter and manager for the offering ("Offering"). The net proceeds from the Offering, after deducting underwriting discounts and commissions and offering expenses were approximately $18,105,100. See "Note 1. Description of Business and Basis of Presentation " of the Notes to Condensed Consolidated Statements for additional detail on the net Offering proceeds.

The following table presents a summary of our net cash flows from operating, investing, and financing activities:

Years End

Cash Provided by (Used in)

December 31, 2025

December 31, 2024

Operating activities

Investing activities

Financing activities

Change in cash and cash equivalents

Consolidated working capital at December 31, 2025 was $19,618,132, compared to $5,329,650 at December 31, 2024, an increase of $14,288,482 or 268.1% due to the July 21, 2025 equity financing Included in working capital were cash and cash

TECOGEN INC.

Table of Contents

equivalents of $12,430,287 at December 31, 2025, compared to $5,405,233 at December 31, 2024, an increase of $7,025,054 or 130.0%, due to July 21, 2025 equity financing proceeds which netted to $18,105,100.

Net cash provided by or used in operating activities

For the year ended December 31, 2025 we used $9,911,674 in cash from operations compared to $4,060,547 in cash generated from operations in 2024, a decrease of $13,972,221 in net cash generated by operating activities. Our accounts receivable balance decreased by $1,682,596 at December 31, 2025 compared to December 31, 2024 and our unbilled revenues decreased by $260,879 at December 31, 2025 compared to December 31, 2024. Our inventory increased by $1,426,182 as of December 31, 2025 compared to December 31, 2024 and other non-current assets decreased by $464,576 as of December 31, 2025 as compared to December 31, 2024.

Accounts payable decreased by $761,131 from December 31, 2024 to December 31, 2025 due to our increased liquidity in the fourth quarter of 2025. Accrued expenses increased by $76,736 as of December 31, 2025 compared to December 31, 2024 due to timing of operating expenses. Deferred revenues decreased by $3,070,219 as of December 31, 2025 as compared to December 31, 2024, due to application of advance customer deposits collected in 2024 for Products shipments in 2025.

Net cash used in investing activities

For the year ended December 31, 2025 we used $464,130, in cash from investing activities. We used $400,781 of cash for purchases of property and equipment, and distributed $67,639 to the 49% non-controlling interest holders of American DG New York LLC and received $4,290 in proceeds from the disposition of assets, including insurance proceeds. Cash used in asset acquisition are mainly for costs incurred in 2025 for initial improvements required to the North Billerica, Massachusetts leased premises which are estimated to range between $1,150,000 and $1,200,000.

For the year ended December 31, 2024 we used $1,014,737 in cash from investing activities. We used $969,163 of cash for purchases of property and equipment, and distributed $96,974 to the 49% non-controlling interest holders of American DG New York LLC and received $51,400 in proceeds from the disposition of assets, including insurance proceeds. Cash used in asset acquisition are mainly for costs incurred in 2024 for initial improvements required to the North Billerica, Massachusetts leased premises.

Net cash provided by financing activities

Cash flows from financing activities for the year ended December 31, 2025 were $17,400,858, During the year ended December 31, 2025, we received $18,105,100 in net proceeds from our follow on equity public offering and received $696,779 of proceeds from the exercise of stock options, we used $1,076,956 to retire a related party note and we used $324,065 of cash in payment of finance lease principal.

During the year ended December 31, 2024, we received proceeds of $1,000,000 under the related party promissory notes and used $62,847 of cash in payment of finance lease principal. and received $71,000 of proceeds from the exercise of stock options (see Note 11."Related Party Notes").

Backlog

Our total product and installation backlog as of December 31, 2025 was $2,522,231 compared to $12,336,248 as of December 31, 2024. Our backlog at December 31, 2024 included an order for several chillers which were shipped in 2025 and orders for several cogeneration systems that shipped in the first quarter of 2025 to customers seeking tax credits under the Inflation Reduction Act of 2022.

Liquidity

At December 31, 2025 and 2024, we had cash and cash equivalents of $12,430,287 and $5,405,233, respectively, an increase of $7,025,054 or 130.0%. During the year ended December 31, 2025, our revenues were negatively impacted due to customer order delays or deferrals; the relocation to our new facility in April 2024 which impacted product revenues during the second and third quarters of 2024; service delays due to customer facility closures, in some cases for extended periods and a reduction in our energy production revenues, due to business closures and increased remote work and learning environments.

Based on our current operating plan, we believe existing resources, including cash and cash flows from operations will be sufficient to meet our working capital requirements for the next twelve months. In order to grow our business, fund the development of our hybrid-drive air-cooled chiller, and respond to opportunities in the data center market, we expect that our cash requirements will increase and we may need to raise additional capital through a debt or equity financing to meet our need for capital to fund operations and future growth. There can be no assurance that we will be able to raise such additional financing or upon terms that are acceptable to us or at all.

TECOGEN INC.

Table of Contents

Repayment of related party notes

On October 9, 2023, we entered into note subscription agreements with each of John N. Hatsopoulos and Earl R. Lewis, III, each a director and shareholder of the Company, pursuant to which Mr. Hatsopoulos agreed to provide financing to us of up to $1,000,000, and Mr. Lewis agreed to provide financing to us of $500,000, and potentially, an additional $500,000 at his discretion. On October 10, 2023, we borrowed $500,000 from Mr. Hatsopoulos and issued him a one-year promissory note with interest accruing at 5.12% per annum. On July 23, 2024, we borrowed an additional $500,000 from Mr. Hatsopoulos and issued a one-year promissory note with interest accruing at 5.06% per annum. On March 21, 2024, we extended the maturity date the of the promissory note dated October 10, 2023 by one-year making the maturity date October 10, 2025. On September 18, 2024, we borrowed $500,000 from Mr. Lewis and issued him a one-year promissory note with interest accruing at 4.57% per annum.

On January 14, 2025, we agreed to permit Mr. Lewis to either receive repayment of his note in cash or, at his discretion, convert the balance of the promissory note into shares of our common stock. In the event of such a conversion, the number of shares we were required to be issued is determined by dividing the balance due under the promissory note by the average closing price per share of our shares during the thirty day period prior to the date of conversion.

On February 18, 2025, we amended the promissory notes with Mr. Hatsopoulos to extend the maturity dates for both promissory notes to July 31, 2026. We also agreed to permit Mr. Hatsopoulos to either receive repayment of his notes in cash, or at his discretion, convert the balance(s) due of one or both of the promissory notes into shares of our common stock. In the event of such a conversion, the number of shares we were required to issue is determined by dividing the balance(s) due under the promissory note(s) by the average closing price per share of our shares during the thirty-day period prior to the date of conversion. Both of the promissory notes with Mr. Hatsopoulos were reclassified to long-term liabilities due to the February 18, 2025 amendment.

The promissory notes were repaid in full or converted to shares of our common stock in the year ended December 31, 2025. See Note 11."Related Party Notes" of the Notes to the Consolidated Financial Statements.

Obligations and Commitments

We are obligated under operating leases for our North Billerica, Massachusetts headquarters through February 28, 2031 and our eleven leased service centers through January 2031. Future minimum lease commitments under non-cancellable operating leases as of December 31, 2025, were $1,543,129.

We are also obligated under finance leases for thirty-five vehicles through October 31, 2029. Future minimum finance lease payments as of December 31, 2025, were $1,272,550.

See Note 14."Leases".

Seasonality

We expect that the majority of our heating systems sales will be operational for the winter and the majority of our chilling systems sales will be operational for the summer. Our cogeneration sales are not generally affected by the seasons. Our service team experiences higher demand in the warmer months when cooling is required. Chiller units for space conditioning applications are generally shut down in the winter and started up again in the spring. This chiller “busy season” for the service team generally runs from May through the end of September. Chillers in indoor cultivation and other process cooling applications run year round.