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 * Lane Brian E.   2. Issuer Name and Ticker or Trading Symbol COMFORT SYSTEMS USA INC [FIX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) President/Chief Executive Off. (Last) (First) (Middle) C/O COMFORT SYSTEMS USA, INC., 675 BERING DRIVE, SUITE 400 3. Date of Earliest Transaction (Month/Day/Year) 04/02/2017 (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 04/02/2018(1)   F   1,091 (2) D $ 40.68 (3) 201,817 D   Common Stock 04/02/2018(1)   F   1,215 (4) D $ 40.68 (3) 200,602 D   Common Stock 04/02/2018(1)   F   1,756 (5) D $ 40.68 (3) 198,846 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

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Lane Brian E. C/O COMFORT SYSTEMS USA, INC. 675 BERING DRIVE, SUITE 400 HOUSTON, TX 77057	X		President/Chief Executive Off.

Signatures

/s/ Trent T. McKenna, by power of attorney		04/04/2018
**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)	Forfeited shares are related to restricted stock units that vested on April 1, 2018 and were priced based on the average of the high and low stock price on April 2, 2018.
(2)	Reflects forfeited shares related to the first vesting of restricted stock units granted on March 8, 2017.
(3)	Price is based on the average of the high and low stock price on April 2, 2018.
(4)	Reflects forfeited shares related to the second vesting of restricted stock units granted on March 23, 2016.
(5)	Reflects forfeited shares related to the third and final vesting of restricted stock units granted on March 25, 2015.

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