Duct and Envelope Tightness (DET) Verifiers are individuals certified to perform duct and envelope tightness testing on residential construction. The term and concept first appeared in the 2011 Georgia Amendments to the 2009 International Energy Conservation Code (IECC). Georgia amended the 2009 IECC to require building envelope leakage testing and eliminated the visual inspection option. Since the 2009 IECC already required duct leakage testing, this meant that both a duct and envelope leakage test would have to be conducted.

In order to ensure some level of accuracy and consistency in the implementation of the testing requirements, the DET Verifier concept was borne. Georgia defined a DET Verifier as a certified Home Energy Rating Systems (HERS) rater, a certified Home Performance with an ENERGY STAR contractor, a Building Performance Institute (BPI) Analyst, or someone who successfully completes a certified DET verifier course that is approved by the Georgia Department of Community Affairs.

There are more than 1,000 certified DET Verifiers across Georgia, filling the critical role of verifying compliance with the energy code’s air leakage requirements. Since Georgia adopted the DET Verifier concept in 2011 it has been adopted to varying degrees at the state and local level in Illinois, South Carolina, Alabama, and Tennessee.

Both the 2012 and 2015 versions of the IECC require mandatory duct and envelope leakage testing for residential construction, but they do not state what qualifications an individual should have to conduct the tests. As those codes get adopted in more states and local jurisdictions, the DET verifier concept should be considered as an effective option for ensuring compliance with the air leakage testing requirements. Defining what qualifications are needed to perform these tests allows builders and code officials to be confident in the results.

For more information on Georgia’s DET Verifier program, read the case study: Residential Performance Testing in Georgia.