NJ Energy Code (484) 443-1010 Check

Duct Leakage Testing

The 2018 IRC/IECC requires comprehensive duct sealing.

If any ducts are outside the thermal envelope, a duct blaster test must be conducted to determine the Total Leakage of the system.

A duct blaster (or duct blower) is portable fan that is installed on a duct system. The registers and grilles are sealed and the fan is used to create positive pressure in the ducts, forcing air out of any leaks.

Total Duct Leakage Diagram

To prepare for the test:

Here is a video showing the steps of a Total Duct Leakage test:

Allowable Limits

The 2018 IRC/IECC specifies different leakage limits depending on the test conditions.  In all cases the limits are based on the conditioned floor area (CFA) of the house:

Total Leakage Limits

(Note:  These limits only apply to projects following a prescriptive compliance pathway.  Projects following a performance or ERI pathway are allowed to trade off higher duct leakage for improved performance in other areas.)


 Duct Test Photo

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