Technical Resources

Demystifying the 2021 IECC Energy Codes:
Your guide to complying with C402.5 and more

Energy (de)Codes

C401.3 Thermal envelope certificate

The 2021 IECC requires a thermal envelope certificate that includes basic information including – R-values, U-factors and the results of air leakage testing.  

EnergyLogic provides C401.3 compliance certificate either as a stand alone service or in conjunction with our air leakage testing services for C402.5.2

C402.1.5 Component performance alternative 

EnergyLogic can provide COMChek reports for projects, but at this time, we only provide the envelope portion of the report. Our dedicated Energy Modeling team, part of EnergyLogic Design Consulting, is ready to assist you with your project.  

C402.5.1.2 Air barrier compliance 

The IECC 2021 mandates that air barrier compliance be demonstrated and in the case of buildings that do not undergo air leakage testing per the exceptions in C405.1.2.  

EnergyLogic provides complete air barrier compliance reports for projects throughout our service area.  

C402.5.1.5 Building envelope performance verification 

EnergyLogic provides building envelope verification per C402.5.1.5. This includes review, inspection and commissioning where required.   

C402.5.2 Dwelling and sleeping unit enclosure testing 

EnergyLogic offers diagnostic testing on buildings of almost any size. We’ve tested structures across Front Range Colorado and beyond. Our team is professional, responsive and detailed. Reports are in compliance with ASTM E779 and ANSI/RESNET/ICC 380. Our testing protocols for either required individual unit tests or sampling protocols follow the code sampling directives.  

C402.5.3 Building thermal envelope testing 

EnergyLogic offers whole building thermal testing to show compliance with C402.5.3. For these tests, our protocols are in compliance with ASTM E779, ANSI/RESNET/ICC 380 and , ASTM E3158 or ASTM E1827.  Our team works closely with project teams to strive for the least disruption to the project. In order to do that we perform pre-test walks and have intensive communication with project teams about vital test preparation.  


C402.5 ​ Air leakage—thermal envelope. 

The building thermal envelope shall comply with Sections C402.5.1 through Section C402.5.11.1, or the building thermal envelope shall be tested in accordance with Section C402.5.2 or C402.5.3. Where compliance is based on such testing, the building shall also comply with Sections C402.5.7, C402.5.8 and C402.5.9.

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