Residential Duct Leak Testing

Tiny leaks in a home's ductwork can mean big problems. Visual inspections alone don't cut it, which is why code regulations mandate pressurized testing of residential duct systems. For contractors and municipalities, it's a matter of choosing a company they can trust to provide the most effective testing methods and reliable results.

At Eastern Air Balance Corporation, we bring an unmatched level of testing knowledge and technical skills paired with the most advanced pressurized testing equipment available today to your project. You can rest assured that our professional technicians are delivering the quality service and problem-solving mindset you'd expect from a trusted testing partner.

In-Depth: Residential Duct Leak Testing

Between 2006 and 2009, revisions to the International Energy Efficiency Code (IEEC) and the International Residential Code (IRC) mandated duct pressure testing of residential HVAC systems and provided maximum allowable leakage criteria when any portion of a duct system in a residential application is installed outside of the "conditioned living area." The IEEC has always had a requirement that ducts be sealed. However the results of numerous studies have found that visual inspection alone cannot assure efficient system operation. Ductwork may be installed in attics or crawl spaces where visual inspection may be difficult or impossible. Pressure testing of duct systems is the only known method to insure minimal leakage which improves operating efficiency. In a further effort to increase HVAC system operating efficiency the code(s) requires that all supply ducts in attics must be insulated to a minimum of R-8 and all other ducts shall be insulated to a minimum of R-6.

A recently conducted study by the Massachusetts Energy Commission of 186 homes found problems with the quality of the duct sealing in over 80% of the homes. Pressurization tests conducted in 22 of the homes found an average leakage rate of 21.6% of the system flow. This illustrates the importance of both proper sealing of duct systems and proper duct leak testing performed by "certified technicians" utilizing "certified test equipment."

A Look at Duct Leak Testing Methods

Both the IEEC and IRC allow for two (2) different types of duct leakage tests to be performed. A "rough in test" can be performed if the duct system installation has been completed and the air handler has not been installed. To perform this test all register boots must be sealed or otherwise blanked off. The supply air or return air system is then pressurized to 0.10" w.c. utilizing a portable duct leak test fan that includes a "certified" orifice tube. The allowable duct leakage must be less than four (4) CFM per 100 Square Feet of conditioned living area.

If the air handler and all supply and return duct is installed a "system test" can be performed. As with the rough in test, all register boots must be sealed or otherwise blanked off. The system including the air handling unit is pressurized to 0.10" w.c. utilizing a portable duct leak test fan that includes a "certified" orifice tube. The allowable duct leakage must be less than six (6) CFM per 100 Square Feet of conditioned living area.

For most installations, it is recommended that the rough in test be performed so that any additional duct sealing that may be required can be performed prior to the installation of drywall and other finishes. Over the past three years, Eastern Air Balance Corporation has successfully completed numerous residential duct leak testing projects in Central Pennsylvania. Eastern Air Balance Corporation can provide the certified duct leak test equipment and National Environmental Balancing Bureau (NEBB) Certified Technicians to successfully complete the duct leak testing for your project.