UNITED STATES
SECURITIES 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) August 13, 2009

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:

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

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

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

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

Item 8.01               Other Events

Attached and incorporated herein by reference as Exhibit 99.1 is a copy of a press release of Comfort Systems USA, Inc., a Delaware corporation (the “Company”) dated August 17, 2009 announcing that its Board of Directors (the “Board”) has approved an amendment to the company’s stock repurchase program to increase the shares authorized and remaining in the program back up to 1,000,000 shares by authorizing the company to acquire up to 476,400 additional shares of its outstanding common stock.  The company’s existing stock repurchase program had previously authorized the repurchase of up to 4,399,009 shares of the company’s outstanding common stock.

Through August 13, 2009, the Company had repurchased 3,875,409 shares of the company’s common stock at an aggregate price of $43,104,805.  This extension of the stock repurchase program will “top off” the plan and permit the Company to repurchase up to an additional 1,000,000 shares of its currently outstanding common stock beyond what had already been purchased as of August 13, 2009.

The share repurchases will be made from time to time at the Company’s discretion in the open market or privately negotiated transactions as permitted by securities laws and other legal requirements, and subject to market conditions and other factors.  The Company expects that the share repurchases will be financed with available cash.  The Company’s Board of Directors may modify, suspend, extend or terminate the program at any time.

Item 9.01               Financial Statements and Exhibits

The following exhibit is included herein:

Exhibit 99.1 Press release dated August 17, 2009 announcing the Board’s approval of the amended stock repurchase program.

 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.

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EXHIBIT INDEX

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Exhibit 99.1

FOR IMMEDIATE RELEASE

COMFORT SYSTEMS INCREASES STOCK REPURCHASE PROGRAM

Houston, TX – August 17, 2009 – Comfort Systems USA, Inc. (NYSE: FIX), a leading provider of commercial, industrial and institutional heating, ventilation and air conditioning (“HVAC”) services, today announced that its Board of Directors has approved an amendment to the company’s stock repurchase program to increase the shares authorized and remaining in the program back up to 1,000,000 shares by authorizing the company to acquire up to 476,400 additional shares of its outstanding common stock.  The company’s existing stock repurchase program had previously authorized the repurchase of up to 4,399,009 shares of the company’s outstanding common stock.

Through August 13, 2009, the Company had repurchased 3,875,409 shares of the company’s common stock at an aggregate price of $43,104,805.  This extension of the stock repurchase program will “top off” the plan and permit the Company to repurchase up to an additional 1,000,000 shares of its currently outstanding common stock beyond what had already been purchased as of August 13, 2009.

The share repurchases will be made from time to time at the Company’s discretion in the open market or privately negotiated transactions as permitted by securities laws and other legal requirements, and subject to market conditions and other factors.  The Company expects that the share repurchases will be financed with available cash.  The Company’s Board of Directors may modify, suspend, extend or terminate the program at any time.

Comfort Systems USAÒ is a premier provider of business solutions addressing workplace comfort, with 76 locations in 69 cities around the nation.  For more information visit the Company’s website at www.comfortsystemsusa.com.

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These statements are based on the current plans and expectations of future events of Comfort Systems USA, Inc. and involve risks and uncertainties that could cause actual future activities and results of operations to be materially different from those set forth in the forward-looking statements.  Important factors that could cause actual results to differ include, among others, the use of incorrect estimates for bidding a fixed-price contract, undertaking contractual commitments that exceed our labor resources, failing to perform contractual obligations efficiently enough to maintain profitability; national or regional weakness in construction activity and economic conditions, financial difficulties affecting projects, vendors, customers, or subcontractors, difficulty in obtaining or increased costs associated with bonding and insurance, shortages of labor and specialty building materials, retention of key management, our backlog failing to translate into actual revenue or profits, errors in our percentage-of-completion method of accounting, the result of competition in our markets, seasonal fluctuations in the demand for HVAC systems, the imposition of past and future liability from environmental, safety, and health regulations including the inherent risk associated with self-insurance, adverse litigation results and other risks detailed in our reports filed with the Securities and Exchange Commission.  A further list and description of these risks, uncertainties and other factors are discussed under “Item 1A. Company Risk Factors.” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2008.  These forward-looking statements speak only as of the date of this filing.  Comfort Systems USA, Inc. expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statement contained herein to reflect any change in our expectations with regard thereto or any change in events, developments, conditions or circumstances on which any such statement is based.