Linda Wetzel of Shaker Heights, Ohio, says she was skeptical about air duct cleaning until a friend told her it had improved her allergies. “I figured common sense said, if there’s dust on the table, there has to be dust in the vents,” Wetzel says.
After hiring an air duct cleaner she found on Angie’s List, Wetzel was very pleased with the results and benefits she experienced. She says she noticed an immediate improvement in air quality — everyone in the house suffered fewer allergies afterward — and the entire HVAC system worked more efficiently.
“We used our air conditioner less in the summer because it had so much more airflow,” she says. “And we used the heater less during an incredibly cold winter.”
Despite such anecdotal experiences, there’s no scientific evidence that regular residential air duct cleaning improves air quality, according to a 1997 brochure published by the Environmental Protection Agency. Laureen Burton, senior scientist in the EPA Indoor Environments Division, says that while the document is nearly two decades old, the science hasn’t changed and the agency stands by its recommendations.
“Checking and changing filters, keeping systems maintained, having regular inspections, and ensuring moisture doesn’t get in are more important,” Burton says.
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The top photo shows the dirty air duct before cleaning, and the bottom photo shows the clean air duct after. (Photo by Eldon Lindsay)
However, both EPA and the National Air Duct Cleaners Association — which represents more than 1,000 cleaning companies nationwide — agree there’s some benefit in cleaning debris from ducts, furnaces, central air conditioners and ventilation.
NADCA consulted on the EPA pamphlet and agrees with all but one of its findings, according to NADCA president Michael Vinick. He says NADCA recommends homeowners clean their ducts once every three to five years. “If you have allergies or asthma, you should consider having it done almost annually,” he says.
The EPA does not recommend that air ducts be cleaned routinely, but only as needed — such as when mold, pests or excessive debris clutter the system. In an online poll, 13 percent of Angie’s List members said they have their ducts cleaned routinely, but 60 percent do so only if serious problems develop.
When do I need to get my air ducts cleaned?
NADCA experts argue the need for cleaning depends on a variety of factors, including pets, smoking, recent renovations, local weather conditions and overall home cleanliness. Vinick says a good contractor will offer to do an inspection beforehand for a nominal charge, if any, to see if a cleaning is necessary.
NADCA’s standards dictate that a cleaning doesn’t just sweep the ducts, but addresses every component air passes over, including coils and the central system. The task involves at least a couple of workers, several hours and costly equipment, which is why air duct cleaning costs $400 or more, according to EPA and NADCA.
A thorough cleaning can yield long-term energy savings. Bob Baker and Ross Montgomery, who study air quality and energy efficiency for the American Society of Heating, Refrigerating and Air-Conditioning Engineers, say their research shows dirty coils and blowers in commercial buildings can cut efficiency by as much as 40 percent.
Vinick calls air duct cleaning an essential part of home maintenance, akin to mopping and vacuuming. “It’s like changing the oil in your car,” he says. “If you don’t change the oil, you’re going to have a problem. When your components are loaded up with debris, the system has to work harder. When you rem