UNITED STATES SECURITIES AND EXCHANGE COMMISSION

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) October 28, 2025

Date of Report (Date of earliest event reported) October 23, 2025

Comfort Systems USA, Inc.

(Exact name of registrant as specified in its charter)

Delaware	1-13011	76-0526487
(State or other jurisdiction	(Commission	(IRS Employer
of incorporation)	File Number)	Identification No.)


675 Bering Drive, Suite 400
Delaware	1-13011	76-0526487
Houston, Texas	77057
(State or other jurisdiction	(Commission	(IRS Employer
(Address of principal executive offices)	(Zip Code)
of incorporation)	File Number)	Identification No.)


675 Bering Drive, Suite 400
Houston, Texas		77057
(Address of principal executive offices)		(Zip Code)

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)

☐¨ ~~Written~~Soliciting material ~~communications~~ pursuant to Rule ~~425~~14a-12 under the ~~Securities~~Exchange Act (17 CFR ~~230~~240.~~425~~14a-12)

☐¨ ~~Soliciting~~Pre-commencement communications ~~material~~ pursuant to Rule ~~14a~~14d-12 2(b) under the Exchange Act (17 CFR 240.~~14a~~14d-122(b))

☐¨ Pre-commencement communications pursuant to Rule ~~14d~~13e-24(bc) under the Exchange Act (17 CFR 240.~~14d~~13e-24(bc))

☐ 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:

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Stock, $0.01 par value		FIX		New York Stock Exchange

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 ¨

~~Emerging~~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 7.01 Regulation FD Disclosure

IfOn anOctober ~~emerging~~28, ~~growth company~~2025, ~~indicate~~Comfort Systems byUSA, ~~check~~Inc., ~~mark~~a ifDelaware corporation (the ~~registrant~~“Company”), ~~has~~a ~~elected~~leading ~~not~~provider toof ~~use~~commercial, ~~the~~industrial ~~extended~~and ~~transition~~institutional heating, ~~period~~ventilation, ~~for~~air ~~complying~~conditioning ~~with~~and ~~any~~electrical ~~new~~contracting orservices, ~~revised~~posted ~~financial~~to ~~accounting~~the ~~standards~~“Investor” ~~provided~~section ~~pursuant~~of toits ~~Section~~Internet website 13(awww.comfortsystemsusa.com) ofan ~~the~~investor ~~Exchange~~presentation ~~Act~~slideshow. ☐The Company intends to use this slideshow in making presentations to analysts, potential investors, and other interested parties.

The information included in the investor presentation includes financial information determined by methods other than in accordance with accounting principles generally accepted in the United States of America (“GAAP”). The Company’s management uses these non-GAAP measures in its analysis of the Company’s performance. The Company believes that the presentation of certain non-GAAP measures provides useful supplemental information that is essential to a proper understanding of the operating results of the Company’s core businesses. These non-GAAP disclosures should not be viewed as a substitute for operating results determined in accordance with GAAP, nor are they necessarily comparable to non-GAAP performance measures that may be presented by other companies.

The information in this Form 8-K being furnished under Item 7.01 shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of such section, nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing. The investor presentation contains forward-looking statements within the meaning of applicable securities laws and regulations. These statements are based on the Company’s expectations and involve risks and uncertainties that could cause the Company’s actual results to differ materially from those set forth in the statements. These risks are discussed in the Company’s filings with the Securities and Exchange Commission, including an extensive discussion of these risks in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024.

A copy of the presentation is furnished herewith as Exhibit 99.1.

ITEM 29.0201 ~~Results~~Financial ofStatements ~~Operations~~ and ~~Financial Condition~~Exhibits

(d) Exhibits.

Attached and incorporated herein by reference as Exhibit 99.1 is a copy of a press release of Comfort Systems USA, Inc. (the “Company”) dated October 23, 2025 reporting the Company’s financial results for the third quarter of 2025.

Exhibit Number		Description

99.1		Investor presentation dated October 28, 2025
104		Cover Page Interactive Data File (the cover page XBRL tags are embedded within the Inline XBRL document).

SIGNATURES

~~The~~Pursuant ~~information~~to ~~contained~~the ~~in this Item 2.02~~ requirements of this Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is being furnished and shall not be deemed “filed” for any purpose, and shall not be deemed incorporated by reference in any filing under the Securities Exchange Act of ~~1933~~1934, ~~as amended, or~~ the ~~Securities~~Registrant ~~Exchange~~has ~~Act~~duly ofcaused ~~1934,~~this asreport ~~amended,~~to ~~except~~be assigned ~~expressly~~on ~~set~~its ~~forth~~behalf by ~~specific~~the ~~reference~~undersigned inhereunto duly ~~such filing~~authorized.

COMFORT SYSTEMS USA, INC. By: /s/ Laura F. Howell Laura F. Howell Senior Vice President and General Counsel

~~ITEM~~Date: October ~~8.01~~28, ~~Other Events~~2025

Attached and incorporated herein by reference as Exhibit 99.2 is a copy of a press release of the Company dated October 23, 2025 reporting the Company’s declaration of a quarterly dividend on the Company’s common stock to stockholders of record as of the close of business on the record date, November 13, 2025.

ITEM 9.01 Financial Statements and Exhibits

(d) The following Exhibits are included herein:

Exhibit 99.1 Press Release of Comfort Systems USA, Inc. dated October 23, 2025 reporting the Company’s financial results for the third quarter of 2025.

Exhibit 99.2 Press Release of Comfort Systems USA, Inc. dated October 23, 2025 reporting the Company’s declaration of a quarterly dividend on the Company’s common stock to stockholders of record as of the close of business on the record date, November 13, 2025.

EXHIBIT INDEX


ExhibitNumber		Exhibit Title or Description

99.1		Press Release of Comfort Systems USA, Inc. dated October 23, 2025 reporting the Company’s financial results for the third quarter of 2025.

99.2		Press Release of Comfort Systems USA, Inc. dated October 23, 2025 reporting the Company’s declaration of a quarterly dividend on the Company’s common stock to stockholders of record as of the close of business on the record date, November 13, 2025.

104		Cover Page Interactive Data File (the cover page XBRL tags are embedded within the Inline XBRL document).

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.

COMFORT SYSTEMS USA, INC. By: /s/ Laura F. Howell Laura F. Howell, Senior Vice President and General Counsel

Date: October 23, 2025

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