<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
	<headerData>
        <submissionType>144</submissionType>
                <filerInfo>
            <filer>
                <filerCredentials>
                    <cik>0001207002</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>
				<com:street1>9753 KATY FREEWAY</com:street1>
                				<com:street2>SUITE 700</com:street2>
                				<com:city>HOUSTON</com:city>
				<com:stateOrCountry>TX</com:stateOrCountry>
				<com:zipCode>77024</com:zipCode>
			</issuerAddress>

			<issuerContactPhone>7138309600</issuerContactPhone>
			<nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Franklin  Myers</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>

			<relationshipsToIssuer>
                                				    <relationshipToIssuer>Director</relationshipToIssuer>

			</relationshipsToIssuer>
		</issuerInfo>

				          <securitiesInformation>
			<securitiesClassTitle>Common</securitiesClassTitle>
			<brokerOrMarketmakerDetails>
				<name>BNY Pershing</name>
				<address>
				<com:street1>240 Greenwich Street</com:street1>
                				<com:city>New York</com:city>
				<com:stateOrCountry>NY</com:stateOrCountry>
				<com:zipCode>10286</com:zipCode>
				</address>
			</brokerOrMarketmakerDetails>
			<noOfUnitsSold>4000</noOfUnitsSold>
			<aggregateMarketValue>6699360</aggregateMarketValue>
			<noOfUnitsOutstanding>35194329</noOfUnitsOutstanding>
			<approxSaleDate>08/11/2026</approxSaleDate>
			<securitiesExchangeName>NYSE</securitiesExchangeName>
		</securitiesInformation>

    		       <securitiesToBeSold>
         <securitiesClassTitle>Common</securitiesClassTitle>
         <acquiredDate>05/18/2010</acquiredDate>
         <natureOfAcquisitionTransaction>Open Market Purchase</natureOfAcquisitionTransaction>
                  <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
                  <isGiftTransaction>N</isGiftTransaction>
		          <amountOfSecuritiesAcquired>5000</amountOfSecuritiesAcquired>
                  <paymentDate>05/18/2010</paymentDate>
                  <natureOfPayment>Open Market Purchase</natureOfPayment>
      </securitiesToBeSold>

    <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>


     <securitiesSoldInPast3Months>
         <sellerDetails>
            <name>Franklin Myers </name>
            <address>
               <com:street1>84 Saddlebrook Lane</com:street1>
                              <com:city>Houston</com:city>
               <com:stateOrCountry>TX</com:stateOrCountry>
               <com:zipCode>77024</com:zipCode>
            </address>
         </sellerDetails>
         <securitiesClassTitle>Common</securitiesClassTitle>
         <saleDate>08/10/2026</saleDate>
         <amountOfSecuritiesSold>3500</amountOfSecuritiesSold>
         <grossProceeds>591652.56</grossProceeds>
      </securitiesSoldInPast3Months>


        <noticeSignature>
            <noticeDate>08/11/2026</noticeDate>
                        <signature>  /s/ Rachel Eslicker, Attorney-in-Fact</signature>
        </noticeSignature>
	</formData>
    </edgarSubmission>
