Exhibit 32.2

CERTIFICATION PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002*

I, William George, Executive Vice President and Chief Financial Officer of Comfort Systems USA, Inc. (the "Company"), certify, pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, 18 U.S. C. Section 1350, that:

The Quarterly Report on Form 10-Q of the Company for the quarter ended March 31, 2009 (the "Report") fully complies with the requirements of Section 13(a) of the Securities Exchange Act of 1934 (15 U.S.C. 78m); and

The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Dated: April 30, 2009

By:
/s/ WILLIAM GEORGE
William George
Executive Vice President and
Chief Financial Officer

*

A signed original of this written statement required by Section 906 has been provided to the Company and will be retained by the Company and furnished to the Securities and Exchange Commission or its staff upon request.