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.”
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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
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 remove that debris, you get energy consumption savings.”
How can I find a good air duct cleaner?
EPA and NADCA agree that if you do hire someone to clean your air ducts, make sure they know what they’re doing — a poor job is worse than no cleaning at all, as it can kick up particles or even break portions of the HVAC system.
Look for air duct cleaners certified by the National Air Duct Cleaners Association. (Photo by Jennica Abrams)
Venice warns homeowners to beware of air duct cleaning scams, especially the sort where unscrupulous cleaners offer a $49 special deal but start piling on extra fees. “It’s a bait and switch scam where they say they’ll offer unlimited cleaning, but then they throw around terms you might not understand, such as extra fees for a ‘main duct line,’” he says. “And many times, these cleaners end up walking out the door with twice the amount of money a reputable duct cleaner would charge. They’ve gotten very sophisticated at upselling.”
Since most states and municipalities don’t license air duct cleaners, you need to check their professional credentials instead, such as NADCA membership. EPA recommends all duct cleaners follow NADCA standards. Member companies must keep at least one technician on staff who has passed a NADCA test. “They have to pass rigorous testing to earn the certificate, and our code of ethics is very important,” Vinick says.
Tom Bergendahl of Wakefield, Massachusetts, wishes he’d hired a reputable service to clean his air ducts instead of a local company that has since gone out of business. “Duct cleaning is a fragile operation, and if you don’t do it right, you can damage the system,” he says. “They completely wrecked the motor.”
The company eventually paid to repair the damage, but Bergendahl still doesn’t feel the work improved air quality or energy efficiency. “Why did I even bother?” he asks.
The cost for quality air duct cleaning averages between $300 and $500. (Photo by Eldon Lindsay)
What are some benefits of duct cleaning?
Despite Bergendahl’s experience, Vinick says NADCA’s certification standards have improved the situation. “A lot of [service companies] weren’t going about it the correct way,” he says. “We have an anti-fraud task force, and we’ve gone after some fraudulent duct cleaners with the help of state attorneys general.” He suggests that in addition to NADCA membership, homeowners make sure their cleaners are an established business, have appropriate insurance and are registered to do business in their state and locality.
Other organizations have also established guidelines. The EPA’s brochure provides a post-cleaning checklist, and in 2007, the Air Conditioning Contractors of Americapublished criteria for HVAC service providers.
While none of the groups claim health benefits from clean air ducts, many Angie’s List members report an improvement. “I haven’t woken up stuffy or congested since,” says Margaret Hopkins of Glen Ellyn, Illinois. “After the cleaning, my home smelled better and there was less dust on my furniture.”
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Experts say research on the health benefits of residential duct cleaning is still in its infancy. Glenn Fellman, the Indoor Air Quality Association’s executive director, says that despite the lack of scientific data, he’s seen and heard much common-sense evidence of improved air quality.
“This is the heart and circulatory system of your house,” Fellman says. “If any of it is gunked up with dust or mold, the core system isn’t going to function correctly.”
Vinick says he’s encountered much anecdotal evidence of the benefits of air duct cleaning. “You could ask the tens of thousands of customers that I’ve had in 26 years about their improved energy consumption and healthy home environment,” he says.
Ultimately, the decision to clean air ducts comes down to a homeowner’s own judgment. “Look at your filter and see if it’s dirty,” Vinick says. “Take a look inside the return grills and supply ductwork and you’ll be able to tell if you have debris buildup.”