<SEC-DOCUMENT>0001950047-25-002793.txt : 20250507
<SEC-HEADER>0001950047-25-002793.hdr.sgml : 20250507
<ACCEPTANCE-DATETIME>20250507162548
ACCESSION NUMBER:		0001950047-25-002793
CONFORMED SUBMISSION TYPE:	144
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20250507
DATE AS OF CHANGE:		20250507

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			COMFORT SYSTEMS USA INC
		CENTRAL INDEX KEY:			0001035983
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRICAL WORK [1731]
		ORGANIZATION NAME:           	05 Real Estate & Construction
		EIN:				760526487
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		144
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	001-13011
		FILM NUMBER:		25921830

	BUSINESS ADDRESS:	
		STREET 1:		675 BERING DRIVE
		STREET 2:		SUITE 400
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77057
		BUSINESS PHONE:		7138309600

	MAIL ADDRESS:	
		STREET 1:		675 BERING DRIVE
		STREET 2:		SUITE 400
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77057

REPORTING-OWNER:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Lane Brian E.
		CENTRAL INDEX KEY:			0001448240
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		144

	MAIL ADDRESS:	
		STREET 1:		COMFORT SYSTEMS USA, INC.
		STREET 2:		675 BERING DRIVE, SUITE 400
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77057
</SEC-HEADER>
<DOCUMENT>
<TYPE>144
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
<XML>
<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:ns2="http://www.sec.gov/edgar/common">
    <headerData>
        <submissionType>144</submissionType>
        <filerInfo>
            <filer>
                <filerCredentials>
                    <cik>0001448240</cik>
                    <ccc>XXXXXXXX</ccc>
                </filerCredentials>
            </filer>
            <liveTestFlag>LIVE</liveTestFlag>



        </filerInfo>
    </headerData>
    <formData>
        <issuerInfo>
            <issuerCik>0001035983</issuerCik>
            <issuerName>COMFORT SYSTEMS USA INC.</issuerName>
            <secFileNumber>001-13011</secFileNumber>
            <issuerAddress>
                <ns2:street1>675 Bring Drive</ns2:street1>
                <ns2:street2>Suite 400</ns2:street2>
                <ns2:city>Houston</ns2:city>
                <ns2:stateOrCountry>TX</ns2:stateOrCountry>
                <ns2:zipCode>77057</ns2:zipCode>
            </issuerAddress>
            <issuerContactPhone>713-830-9600</issuerContactPhone>
            <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>BRIAN E LANE</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
            <relationshipsToIssuer>
                <relationshipToIssuer>Officer</relationshipToIssuer>
                <relationshipToIssuer>Director</relationshipToIssuer>
            </relationshipsToIssuer>
        </issuerInfo>
        <securitiesInformation>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <brokerOrMarketmakerDetails>
                <name>Morgan Stanley Smith Barney LLC Executive Financial Services</name>
                <address>
                    <ns2:street1>1 New York Plaza</ns2:street1>
                    <ns2:street2>8th Floor</ns2:street2>
                    <ns2:city>New York</ns2:city>
                    <ns2:stateOrCountry>NY</ns2:stateOrCountry>
                    <ns2:zipCode>10004</ns2:zipCode>
                </address>
            </brokerOrMarketmakerDetails>
            <noOfUnitsSold>15000</noOfUnitsSold>
            <aggregateMarketValue>6474874.50</aggregateMarketValue>
            <noOfUnitsOutstanding>35274843</noOfUnitsOutstanding>
            <approxSaleDate>05/07/2025</approxSaleDate>
            <securitiesExchangeName>NYSE</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>04/01/2024</acquiredDate>
            <natureOfAcquisitionTransaction>Compensation for Past Services</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>8444</amountOfSecuritiesAcquired>
            <paymentDate>04/01/2024</paymentDate>
            <natureOfPayment>Compensation</natureOfPayment>
        </securitiesToBeSold>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>04/02/2018</acquiredDate>
            <natureOfAcquisitionTransaction>Compensation for Past Services</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>1046</amountOfSecuritiesAcquired>
            <paymentDate>04/02/2018</paymentDate>
            <natureOfPayment>Compensation</natureOfPayment>
        </securitiesToBeSold>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>03/20/2024</acquiredDate>
            <natureOfAcquisitionTransaction>Compensation for Past Services</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>4584</amountOfSecuritiesAcquired>
            <paymentDate>03/20/2024</paymentDate>
            <natureOfPayment>Compensation</natureOfPayment>
        </securitiesToBeSold>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>03/07/2018</acquiredDate>
            <natureOfAcquisitionTransaction>Compensation for Past Services</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>926</amountOfSecuritiesAcquired>
            <paymentDate>03/07/2018</paymentDate>
            <natureOfPayment>Compensation</natureOfPayment>
        </securitiesToBeSold>
        <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
        <noticeSignature>
            <noticeDate>05/07/2025</noticeDate>
            <planAdoptionDates/>
            <signature>/s/ Brian E Lane</signature>
        </noticeSignature>
    </formData>
</edgarSubmission>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
