FSEC researchers discovered this while conducting a study measuring leakage of installed air handlers. The Florida Department of Community Affairs code division funded the study, titled “Field Testing to Characterize the Airtightness and Operating Pressures of Residential Air Handlers.”

FSEC researchers Chuck Withers and Jim Cummings — along with help from Janet MacIlvaine, Jeff Sonne, and Matt Lombardi — measured air handler and duct leakage in 30 homes built last year in Central Florida.

The group found leakage in ductwork was higher than expected. Withers said he was disappointed that “after several years of educating and training many contractors about the severity of duct leakage, we are still finding significant amounts of duct leakage in the homes.”

FSEC also says that if contractors do a good job of sealing the ductwork, the air handling cabinet they purchase from the manufacturer can be leaky,

Wasting conditioned air isn’t the only problem resulting from a leaky system, according to the center. A leaky air handler in the garage can draw in car exhaust fumes or toxins from chemicals stored near it. According to the study, the average installed air handler cabinet allows 6% of the system’s airflow to leak in from the garage or attic. The best location for the entire system, ducts, and air handler is in the conditioned space, according to the study.

“The good news is there are test methods and qualified people to evaluate the overall efficiency of the air distribution system,” said Withers. “Most homeowners, even those who recently moved into new homes, may be well advised to take advantage of any utility or independent duct-sealing programs.”

Publication date: 04/22/2002