8-K

UNITED STATESSECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT

REPORT

Pursuant

to Section 13 OR 15(d) of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported) March 10, 2021

Comfort Systems USA, Inc.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code

(713) 830-9600

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

ITEM 4.01. Changes in Registrant’sCertifying Accountant.

On March 10, 2021, the Audit Committee (the “Committee”) of the Board of Directors of Comfort Systems USA, Inc. (the “Company”), following a competitive request for proposal process, approved the engagement of Deloitte & Touche LLP (“Deloitte”), subject to the completion of Deloitte’s customary client acceptance procedures, as the Company’s independent registered public accounting firm for the year ending December 31, 2021, and dismissed Ernst & Young LLP (“EY”) as the Company’s independent registered public accounting firm, each effective immediately.

EY’s audit reports on the Company’s consolidated financial statements as of and for the fiscal years ended December 31, 2020 and 2019 did not contain an adverse opinion or a disclaimer of opinion and were not qualified or modified as to uncertainty, audit scope or accounting principles.

During the fiscal years ended December 31, 2020 and 2019, and the subsequent interim periods through March 10, 2021, there were (i) no disagreements (as described in Item 304(a)(1)(iv) of Regulation S-K and the related instructions) between the Company and EY on any matter of accounting principles or practices, financial statement disclosure, or auditing scope or procedure, which, if not resolved to EY’s satisfaction, would have caused EY to make reference thereto in their reports on the financial statements for such years, and (ii) no “reportable events” within the meaning of Item 304(a)(1)(v) of Regulation S-K.

The Company provided EY with a copy of the disclosures it is making in this Current Report on Form 8-K and requested that EY furnish a letter addressed to the Securities and Exchange Commission stating whether or not it agrees with the statements made herein. A copy of EY’s letter dated March 15, 2021 is filed as Exhibit 16.1 hereto.

During the fiscal years ended December 31, 2020 and 2019, and the subsequent interim periods through March 10, 2021, neither the Company nor anyone acting on its behalf has consulted with Deloitte regarding (i) the application of accounting principles to a specific transaction, either completed or proposed, or the type of audit opinion that might be rendered on the Company’s financial statements or the effectiveness of internal control over financial reporting, and neither a written report nor oral advice was provided to the Company that Deloitte concluded was an important factor considered by the Company in reaching a decision as to any accounting, auditing, or financial reporting issue, (ii) any matter that was the subject of a disagreement within the meaning of Item 304(a)(1)(iv) of Regulation S-K, or (iii) any reportable event within the meaning of Item 304(a)(1)(v) of Regulation S-K.

ITEM

9.01        Financial Statements and Exhibits

(d) The following Exhibits are included herein:

Exhibit 16.1 Letter to Securities and Exchange Commission from Ernst & Young LLP, dated March 15, 2021.

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EXHIBIT INDEX

3

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date:      March 15, 2021

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Exhibit 16.1

March 15, 2021

Securities and Exchange Commission

100 F Street, N.E.

Washington, DC 20549

Ladies and Gentlemen:

We have read Item 4.01 of Form 8-K dated March 15, 2021, of Comfort Systems USA, Inc. and are in agreement with the statements contained in the 2^nd^, 3^rd^ and 4^th^ paragraphs on page 2 therein. We have no basis to agree or disagree with other statements of the registrant contained therein.

March 15, 2021

A member firm of Ernst & Young Global Limited