A Plus, Inc, Insulation Materials, Decatur, GA

DET Certification - New Construction

On January 1st, 2011, with the implementation of the new Energy Codes, Duct and Envelope Tightness (DET) verification and testing became mandatory for all new residential building permits issued on or after July 1st, 2011.

This is required for all new residential construction.   For complete code information refer to 2011 Georgia State Supplements and Amendments.


a plus, inc. has 5 DET Verifiers on staff to perform this testing.  Contact us at 404-373-plus (7587) or sales@aplusinc.net to schedule the testing.


Residential Definitions     Allowable Leakage Rates     Specifications for DET verifier     Test requirements


Allowable Leakage Rates:

In simple, general terms, the maximum allowable leakage rates for the building envelope and for duct systems that are outside the building envelope are shown below:


Blower Door Testing:

The building envelope must achieve fewer than 7 air changes per hour at 50 Pascals (7 ACH50).

This test can only be done 'post-construction'.


Duct System Testing:

Duct system can be tested at rough-in or post construction with the 'Total Leakage' test OR at post construction with the 'Leakage to Outside' test.

Rough-In Total Leakage (RIT) must be less than 6 CFM25 per 100 SF of conditioned floor area served by that particular duct system.

Post-Construction Total Leakage (PCT) must be less than 12 CFM25 per 100 SF of conditioned floor area served by that particular duct system.

Post-Construction Leakage to Outside (PCO) must be less than 8 CFM25 per 100 SF of conditioned floor area served by that particular duct system.


Specifications for a DET verifier:

Testing for building envelope and duct tightness shall be conducted by a certified DET verifier. 

A certified DET verifier shall be:

A Building Performance Institute (BPI) analyst;  or

Successfully completed a certified DET verifier course that is approved by the Georgia Department of Community Affairs; or

A Certified Home Energy Rating Systems (HERS) rater;  or

A Certified Home Performance with ENERGY STAR contractor.


Test Requirements:

The required envelope and duct tightness testing is accomplished by using a blower door and duct blaster pressure testing system.

The results of the envelope and duct tightness test are required to be filled out by the DET Verifier on a permanent certificate that is posted on or near the electric panel or air handler.

If the test fails, then nothing is recorded until there is a successful retest.

The top portion of the certificate is filled out by the builder, and the mechanical portion by the HVAC contractor.

Download a copy of the Certificate here

Download a copy of the instructions here


Residential Definitions:

Residential buildings include:

One and two family dwellings (R-3);

Multi-family apartment buildings (R-2); and

Residential care / assisted living facilities (R-4) that are 3 stories or less in height above grade.