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  <element id="fix_SelfInsuranceAmountOfLossFullyInsuredAboveDeductibleCoverageAmount" name="SelfInsuranceAmountOfLossFullyInsuredAboveDeductibleCoverageAmount" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element name="SelfInsuranceDeductibleAmountPerIncident" id="fix_SelfInsuranceDeductibleAmountPerIncident" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="SelfInsuranceDeductibleAmountPerPersonPerPolicy" id="fix_SelfInsuranceDeductibleAmountPerPersonPerPolicy" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="SelfInsuranceAggregateLossInsuranceCoveredAmount" id="fix_SelfInsuranceAggregateLossInsuranceCoveredAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="SelfInsuranceNumberOfMedicalPlans" id="fix_SelfInsuranceNumberOfMedicalPlans" type="xbrli:integerItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" />
  <element id="fix_WorkersCompensationMember" name="WorkersCompensationMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element name="SalesRevenueMember" id="fix_SalesRevenueMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LifeInsuranceContractsNumberOfEmployeesCovered" id="fix_LifeInsuranceContractsNumberOfEmployeesCovered" type="xbrli:integerItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="LifeInsuranceContractsFaceAmount" id="fix_LifeInsuranceContractsFaceAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="EmployeeAndNonemployeeStockOptionMember" id="fix_EmployeeAndNonemployeeStockOptionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LiabilitiesDueToFormerOwnersCurrent" id="fix_LiabilitiesDueToFormerOwnersCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <element id="fix_DebtInstrumentCovenantNetEarningsUsedForCalculationOfCreditFacilityAdjustedEBITDANumberOfQuarters" name="DebtInstrumentCovenantNetEarningsUsedForCalculationOfCreditFacilityAdjustedEBITDANumberOfQuarters" nillable="true" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardSumOfAgeAndYearsOfServiceForAcceleratedVestingOnRetirement" id="fix_ShareBasedCompensationArrangementByShareBasedPaymentAwardSumOfAgeAndYearsOfServiceForAcceleratedVestingOnRetirement" type="xbrli:durationItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="TypesOfPerformanceStockUnits" id="fix_TypesOfPerformanceStockUnits" type="xbrli:integerItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PerformanceMultiplierForDollarDenominatedAwardGranted" id="fix_PerformanceMultiplierForDollarDenominatedAwardGranted" type="xbrli:pureItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PeriodForWhichShareholderReturnIsComparedWithPeerGroupForUnitsDeterminedByEPSPerformance" id="fix_PeriodForWhichShareholderReturnIsComparedWithPeerGroupForUnitsDeterminedByEPSPerformance" type="xbrli:durationItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PercentageOfUnitsMeasuredOnStockPriceRelativeToGroupOfPeer" id="fix_PercentageOfUnitsMeasuredOnStockPriceRelativeToGroupOfPeer" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PercentageOfUnitsMeasuredOnPredeterminedEPS" id="fix_PercentageOfUnitsMeasuredOnPredeterminedEPS" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <element id="fix_LineOfCreditBorrowingCapacityAccordionOption" name="LineOfCreditBorrowingCapacityAccordionOption" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_DebtInstrumentVariableRateSecondaryClassificationAxis" name="DebtInstrumentVariableRateSecondaryClassificationAxis" nillable="true" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_DebtInstrumentVariableRateSecondaryClassificationDomain" name="DebtInstrumentVariableRateSecondaryClassificationDomain" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_DebtInstrumentVariableRateFederalFundsRateMember" name="DebtInstrumentVariableRateFederalFundsRateMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_DeferredAcquisitionPayments" name="DeferredAcquisitionPayments" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_AccruedJobLosses" name="AccruedJobLosses" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_SharebasedCompensationPerformanceSharesAwardCalculatedFairMarketValueCurrentPortion" name="SharebasedCompensationPerformanceSharesAwardCalculatedFairMarketValueCurrentPortion" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_SubordinateDebtAndPromissoryNoteMember" name="SubordinateDebtAndPromissoryNoteMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_StockRepurchaseProgram2007Member" name="StockRepurchaseProgram2007Member" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_OmnibusIncentivePlan2017Member" name="OmnibusIncentivePlan2017Member" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesBillingsInExcessOfCostsAndEstimatedEarnings" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesBillingsInExcessOfCostsAndEstimatedEarnings" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_CashFlowDiscountRate" name="CashFlowDiscountRate" nillable="true" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_CustomerRelationshipsNonCompeteAgreementsAndTradenamesMember" name="CustomerRelationshipsNonCompeteAgreementsAndTradenamesMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_EmployeeMedicalPlanThreeMember" name="EmployeeMedicalPlanThreeMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_NewConstructionMember" name="NewConstructionMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_ExistingBuildingConstructionMember" name="ExistingBuildingConstructionMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_ServiceCallsMaintenanceAndMonitoringMember" name="ServiceCallsMaintenanceAndMonitoringMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_EducationMember" name="EducationMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_RetailRestaurantsAndEntertainmentMember" name="RetailRestaurantsAndEntertainmentMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_MultiFamilyAndResidentialMember" name="MultiFamilyAndResidentialMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_PercentageOfRevenueFromContractWithCustomer" name="PercentageOfRevenueFromContractWithCustomer" nillable="true" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_ReceivableDueTerm" name="ReceivableDueTerm" nillable="true" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_PaymentsReceivedTerm" name="PaymentsReceivedTerm" nillable="true" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_RenewableServiceMaintenanceAgreementsTerm" name="RenewableServiceMaintenanceAgreementsTerm" nillable="true" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_ServiceProjectsMember" name="ServiceProjectsMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_OfficeBuildingCustomerMember" name="OfficeBuildingCustomerMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_HealthcareSectorCustomerMember" name="HealthcareSectorCustomerMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_GovernmentCustomerMember" name="GovernmentCustomerMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_NumberOfOptionsToRenew" name="NumberOfOptionsToRenew" nillable="true" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_SupplementalInformationRelatedToLeasesAbstract" name="SupplementalInformationRelatedToLeasesAbstract" nillable="true" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_ScheduleOfLeaseAssetsAndLiabilitiesTableTextBlock" name="ScheduleOfLeaseAssetsAndLiabilitiesTableTextBlock" nillable="true" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_ScheduleOfSupplementalInformationRelatedToLeasesTableTextBlock" name="ScheduleOfSupplementalInformationRelatedToLeasesTableTextBlock" nillable="true" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_VariableLeaseAndShortTermLeaseCost" name="VariableLeaseAndShortTermLeaseCost" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_BusinessCombinationConsiderationTransferredWorkingCapitalAdjustment" name="BusinessCombinationConsiderationTransferredWorkingCapitalAdjustment" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_ChangeInRightOfUseAssets" name="ChangeInRightOfUseAssets" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_StockRepurchaseProgramAdditionalNumberOfSharesAuthorizedToBeRepurchased" name="StockRepurchaseProgramAdditionalNumberOfSharesAuthorizedToBeRepurchased" nillable="true" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_DeferredTaxAssetsLeaseLiability" name="DeferredTaxAssetsLeaseLiability" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_ServicesActivityMember" name="ServicesActivityMember" nillable="true" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_UnbilledAccountsReceivableAllowanceForCreditLoss" name="UnbilledAccountsReceivableAllowanceForCreditLoss" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_WeightedAverageCostOfCapital" name="WeightedAverageCostOfCapital" nillable="true" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="fix_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsCostsInExcessOfBillings" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsCostsInExcessOfBillings" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element name="DebtMaturityDateAxis" id="fix_DebtMaturityDateAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DebtMaturityDateDomain" id="fix_DebtMaturityDateDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="MaturityYearOneMember" id="fix_MaturityYearOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="MaturityYearTwoMember" id="fix_MaturityYearTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="MaturityYearThreeMember" id="fix_MaturityYearThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="MaturityYearFourMember" id="fix_MaturityYearFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IncomeTaxExaminationInterestIncomeExpenseNet" id="fix_IncomeTaxExaminationInterestIncomeExpenseNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="FederalIncomeTaxBenefitTaxCreditsResearch" id="fix_FederalIncomeTaxBenefitTaxCreditsResearch" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="TaxYears2019To2021Member" id="fix_TaxYears2019To2021Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RevenueRecognitionInitialApplicationPeriodCumulativeEffectTransitionAxis" id="fix_RevenueRecognitionInitialApplicationPeriodCumulativeEffectTransitionAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RevenueRecognitionInitialApplicationPeriodCumulativeEffectTransitionDomain" id="fix_RevenueRecognitionInitialApplicationPeriodCumulativeEffectTransitionDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DebtInstrumentCovenantInterestCoverageRatio" id="fix_DebtInstrumentCovenantInterestCoverageRatio" type="xbrli:pureItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="DebtInstrumentCovenantNumberOfQuartersOfConsolidatedAdjustedEbitdaAndInterestExpenseUsedForCalculationOfInterestCoverageRatioNumberOfQuarters" id="fix_DebtInstrumentCovenantNumberOfQuartersOfConsolidatedAdjustedEbitdaAndInterestExpenseUsedForCalculationOfInterestCoverageRatioNumberOfQuarters" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="NetLeverageRatioLessThanOrEqualTo3.25Member" id="fix_NetLeverageRatioLessThanOrEqualTo3.25Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="NetLeverageRatioLessThanOrEqualTo2.75Member" id="fix_NetLeverageRatioLessThanOrEqualTo2.75Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DebtInstrumentVariableRateOneMonthSofrMember" id="fix_DebtInstrumentVariableRateOneMonthSofrMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DebtInstrumentVariableRateSixMonthSofrMember" id="fix_DebtInstrumentVariableRateSixMonthSofrMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DebtCovenantRatioRangeFiveMember" id="fix_DebtCovenantRatioRangeFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DebtInstrumentCovenantNetLeverageRatioTotalIndebtednessCashAdjustment" id="fix_DebtInstrumentCovenantNetLeverageRatioTotalIndebtednessCashAdjustment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="DeferredTaxAssetsResearchAndExperimentalExpenditures" id="fix_DeferredTaxAssetsResearchAndExperimentalExpenditures" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="InterestExpenseIncomeOnInterestRateSwaps" id="fix_InterestExpenseIncomeOnInterestRateSwaps" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="DebtInstrumentVariableRateThreeMonthSofrMember" id="fix_DebtInstrumentVariableRateThreeMonthSofrMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CumulativeNumberOfCompaniesAcquiredOutstandingNotesToFormerOwners" id="fix_CumulativeNumberOfCompaniesAcquiredOutstandingNotesToFormerOwners" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="EldecoincMember" id="fix_EldecoincMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="TechnologyMember" id="fix_TechnologyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="BusinessCombinationContingentConsiderationChangeInContingentConsiderationLiabilityMember" id="fix_BusinessCombinationContingentConsiderationChangeInContingentConsiderationLiabilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DisputeWithCustomerMember" id="fix_DisputeWithCustomerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="GrossProfitMember" id="fix_GrossProfitMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ManufacturingCustomerMember" id="fix_ManufacturingCustomerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="MechanicalSegmentMember" id="fix_MechanicalSegmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ElectricalSegmentMember" id="fix_ElectricalSegmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DeccoIncMember" id="fix_DeccoIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="NumberOfOffSiteConstructionRealEstateLeasesCommenced" id="fix_NumberOfOffSiteConstructionRealEstateLeasesCommenced" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="CustomerOneMember" id="fix_CustomerOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="NumberOfCustomers" id="fix_NumberOfCustomers" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ConstructionContractorRetainagePayable" id="fix_ConstructionContractorRetainagePayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="TwentyTwentyThreePerformanceSharesGrantMember" id="fix_TwentyTwentyThreePerformanceSharesGrantMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="TwentyTwentyTwoPerformanceSharesGrantMember" id="fix_TwentyTwentyTwoPerformanceSharesGrantMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="TwentyTwentyOnePerformanceSharesGrantMember" id="fix_TwentyTwentyOnePerformanceSharesGrantMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ContractNetAssetsIncrease" id="fix_ContractNetAssetsIncrease" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="ContractNetLiabilitiesIncrease" id="fix_ContractNetLiabilitiesIncrease" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ScheduleOfShareBasedPaymentAwardPerformanceStockUnitsValuationAssumptionsTableTextBlock" id="fix_ScheduleOfShareBasedPaymentAwardPerformanceStockUnitsValuationAssumptionsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="BusinessCombinationNumberOfEarningsMilestones" id="fix_BusinessCombinationNumberOfEarningsMilestones" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="BusinessCombinationTermOfEarningsMilestones" id="fix_BusinessCombinationTermOfEarningsMilestones" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeaseRightOfUseAssets" id="fix_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeaseRightOfUseAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOperatingLeaseLiabilities" id="fix_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOperatingLeaseLiabilities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriodPercentage" id="fix_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriodPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="SummitIndustrialConstructionLlcMember" id="fix_SummitIndustrialConstructionLlcMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedOperatingLeaseObligation" id="fix_BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedOperatingLeaseObligation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="JSMechanicalContractorsIncMember" id="fix_JSMechanicalContractorsIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="MechanicalContractorNorthCarolinaMember" id="fix_MechanicalContractorNorthCarolinaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="OtherDebtMember" id="fix_OtherDebtMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="VariableRateWellsFargoBankNPrimeRateMember" id="fix_VariableRateWellsFargoBankNPrimeRateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="EmployersLiabilityMember" id="fix_EmployersLiabilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AutoLiabilityMember" id="fix_AutoLiabilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="TwentyTwentyFourPerformanceSharesGrantMember" id="fix_TwentyTwentyFourPerformanceSharesGrantMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ScheduleOfBalanceSheetPresentationOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" id="fix_ScheduleOfBalanceSheetPresentationOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="DebtInstrumentVariableRateBaseRateMember" id="fix_DebtInstrumentVariableRateBaseRateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="LiabilitiesDueToCustomersCurrent" id="fix_LiabilitiesDueToCustomersCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="DeferredTaxAssetsGoodwill" id="fix_DeferredTaxAssetsGoodwill" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
</xsd:schema>
