COMFORT SYSTEMS USA INC

To the stockholders and the Board of Directors of Comfort Systems USA, Inc.

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Comfort Systems USA, Inc. and its consolidated subsidiaries (the “Company”) as of December 31, 2023 and 2022, the related consolidated statements of operations, stockholders’ equity, and cash flows, for each of the three years in the period ended December 31, 2023, and the related notes (collectively, referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2023 and 2022, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2023, in conformity with accounting principles generally accepted in the United States of America.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company’s internal control over financial reporting as of December 31, 2023, based on criteria established inInternal Control — Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission and our report dated February 22, 2024, expressed an unqualified opinion on the Company’s internal control over financial reporting.

Basis for Opinion

These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current-period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of this critical audit matter does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Revenue from Contracts with Customers – Refer to Notes 2 and 3 to the Consolidated Financial Statements

Critical Audit Matter Description

The Company recognizes revenue based on the extent of progress towards completion of the performance obligation. The Company generally uses a cost-to-cost input method to measure progress for its contracts, as it depicts the transfer of assets to the customer that occurs as the Company incurs costs, which include labor, materials, subcontractors’ costs, other direct costs, and an allocation of indirect costs. Under the cost-to-cost measure of progress, the extent of progress towards completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance obligation. Revenue, including estimated fees or profits, is recorded proportionally as costs are incurred.

The cost-to-cost input method of accounting is also affected by changes in job performance, job conditions, and final contract settlements. These factors may result in revisions to estimated costs and, therefore, revenue. Such revisions are

frequently based on further estimates and subjective assessments. Variations from estimated project costs could have a significant impact on operating results, depending on project size, and the recoverability of the variation from change orders collected from customers.

Given the judgments necessary to account for the Company’s contracts with customers, specifically the estimates of total costs that will be incurred at contract completion, which are complex and subject to many variables, auditing the corresponding balances and related accounting estimates required extensive audit effort due to the complexity of these estimates, and a high degree of auditor judgment when performing audit procedures and evaluating the results of those procedures.

How the Critical* Audit Matter Was Addressed in the Audit*

Our audit procedures related to management’s estimates and judgments included within the Company’s estimated total costs at contract completion for its contracts with customers included the following, among others:

/s/Deloitte & Touche LLP

Houston, Texas

February 22, 2024

We have served as the Company’s auditor since 2021.