Duct Leakage Testing

Why Test Your Ducts for Leakage?

  Most Florida homes have their ductwork in the unconditioned attics. Properly sealed and insulated ducts deliver the expensive conditioned air where we want it, inside our living spaces. Code compliance credit for properly sealed ducts is only one of many reasons for this low-cost measure. There are two primary duct leakage tests that can be performed (See descriptions below). Here are just a few benefits of testing the ductwork and properly sealing the leaks:

Increased home comfort and reduced HVAC operating costs.

Improved indoor air quality, reduced health & safety issues caused by duct leakage. 

Reduced installation costs by remediating problems at rough-in.

Improved installation quality control, providing an optimal performing duct system.

Better contractor performance as work is inspected & tested with flaws remediated.

Increased eligibility for energy efficiency programs which require specific duct leakage results for program participation.

Temporary protection from duct system contamination when tested early during construction by leaving the register masking in place. 

We are IDL Certified (Infiltration & Duct Leakage) by the Building Performance Institute. Our Duct Leakage and Blower Door tests are performed by our Licensed Home Inspectors. 

"Leaky ducts in your attic (Red) greatly reduce efficiency costing you money and comfort."

"Leaky ducts in your attic (Red) greatly reduce efficiency costing you money and comfort."


Additional Code Information

  Duct leakage testing is described in the IECC (Section R403.3.3) for all new residential construction. This and other recent changes in the Florida Energy Code may require builders to re-evaluate energy efficiency measures included in their homes in order to pass code. One credit, the leak-free duct credit, provides a 9 percent benefit for code compliance. For comparative purposes, including this credit has about the same impact as raising the air conditioning (AC) system SEER rating from 13 to 15.  However, verification is required by a state approved, qualified technician.

Leak-Free Duct Credit Specifics

To receive the duct system credit, leakage must be less than 3 percent Total Duct Leakage (3 cfm/100 square feet),  OR the leakage must be less than 9 percent Total Duct Leakage, and less than 3 percent leakage to unconditioned spaces (Outside Leakage). Since less than 3 percent Total Duct Leakage is extremely difficult to achieve (air handlers alone leak 1-3 percent), the second option, is the method more likely to be successful.

A blower door must be used in conjunction with a duct tester to measure Leakage to the Outside. The duct tester alone is used to measure Total Duct Leakage. The blower door-duct tester combination is required to test for the practical and achievable option. No substitutes for estimating duct leakage are allowed. When claiming the duct leakage credit, measured test results are recorded on the State’s duct and energy code compliance Form and must be submitted to the building department, signed by both the certified technician and building official.