FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * GEORGE WILLIAM III   2. Issuer Name and Ticker or Trading Symbol COMFORT SYSTEMS USA INC [FIX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Chief Financial Officer (Last) (First) (Middle) C/O COMFORT SYSTEMS USA, INC., 675 BERING DRIVE, SUITE 400 3. Date of Earliest Transaction (Month/Day/Year) 03/25/2010 (Street) HOUSTON, TX 77057 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 04/01/2010   F   2,042 (1) D $ 12.67 (2) 80,634 D   Common Stock 04/01/2010   F   1,917 (3) D $ 12.67 (2) 78,717 D   Common Stock 03/25/2010   A   22,948 A (4) 101,665 D

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Incentive Stock Option (Option to Buy)

$ 12.46

03/25/2010

A

19,124

(5)

(6)

Common Stock

19,124

$ 12.46

120,789

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
GEORGE WILLIAM III C/O COMFORT SYSTEMS USA, INC. 675 BERING DRIVE, SUITE 400 HOUSTON, TX 77057			Chief Financial Officer

Signatures

/s/ William George III		04/06/2010
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Reflects third and final vesting of the Performance Stock Award dated March 28, 2007.
(2)	Price is based on the Company's high and low daily stock price average on April 1, 2010.
(3)	Reflects second vesting of the Performance Stock Award dated March 26, 2008.
(4)	Award pursuant to Performance Restricted Stock Agreement; stock vests pursuant to performance and longevity conditions over a three-year vesting schedule.
(5)	Options vest in equal installments on each of the first three anniversaries from the date of grant.
(6)	Options will expire at the earlier of ten years from the date of grant or three months following termination of employment.

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