Living Smart: How often should you clean your air ducts?

McClatchy-Tribune Information Services

Many homeowners who’ve hired a reputable air duct cleaning contractor are often pleased with the results. While there’s no scientific evidence to prove that vent cleaning has a direct and significant benefit, experts agree there’s some benefit to having air duct cleaning performed, particularly if you hire a skilled professional.

The National Air Duct Cleaners Association recommends getting your air ducts cleaned every three to five years. Ed Mack, owner of Air Duct Professionals in Lake Elsinore, Calif., says homeowners should consider doing it every two to five years, depending on their circumstances.

"How often you need it will depend on what part of the country you’re in, how often you use your system, and if anyone in your home has allergies or asthma," Mack says.

The Environmental Protection Agency recommends cleaning air ducts when:

— You suspect that mold exists in the air ducts.

— You notice a vermin infestation somewhere in the home, or you see insects or rodents entering or exiting ductwork.

— You see a visible "poof" of dust released from the supply registers when air is exiting the vents.

Mack recommends taking a look inside your air vent register.

"If you notice black debris around the outside, that’s pollutants that have been recycled through the system over and over again, and that’s a sign your system is excessively soiled," he says. "Also, take a look at your system when you change your filter. If there’s a lot of dust buildup in that area, that’s another sign you’re overdue for a cleaning."

Most experts, including the EPA, have not endorsed air duct cleaning as a remedy for health issues, but cleaners say they’ve amassed a growing body of anecdotal evidence that it does provide some benefit.

"I’ve had tens of thousands of customers over 26 years that will tell you they’ve enjoyed the benefits of air duct cleaning to their environment," says Michael Vinick, NADCA president.

Mack says a proper air duct cleaning will help with the biggest causes of respiratory problems. "If you have asthma, your number one enemy is dust mites," he says. "And for people with allergies, pollen and dander are a big problem. These are microscopic elements you can’t see with the naked eye, and they’re commonly found in air ducts. A good cleaning will remove a lot of them."

However, NADCA standards caution that these elements will only be removed by a thorough cleaning that addresses every part of the system that air moves across, not just the air ducts.

"A good cleaner is going to use a negative air machine and a rotary brush cabling system," Mack says. "The brush goes through the ducts and knocks the debris loose, and the negative air machine vacuums it away."

NADCA says homeowners should clean air ducts under these circumstances:

— Every three to five years. Be wary of a contractor who suggests more frequent cleanings.

— When you move into a new home, unless you know the previous homeowner serviced the air ducts within the last three years.

— After building a new home. It’s likely the ducts have built up debris from drywall dust and other materials used during the construction phase.

— After completing a home remodeling project. Construction projects spread sawdust throughout the home, and unless you go to lengths to protect the ducts, the dust will extend into the ductwork.

— If you have pets in the home that shed fur and dander. Duct cleaning and effective home cleaning practices can help to prevent it from spreading throughout the home.

Professionals warn homeowners to avoid air duct cleaning scams and stay away from excessively cheap specials that seem too good to be true.

"You don’t want to go with the ‘$49 bandits,’" Mack says. "These are less reputable contractors who will use the very, very low price to get into your house and then keep piling on the extra charges."

Keep these points in mind when hiring an air duct cleaning company:

— A good duct cleaning costs between $400 and $1,000 and addresses every aspect of the system that air passes over, including the furnace, air coils and central system. Good cleaners will use negative air machines with HEPA filters.

— It should take a few hours. An air duct cleaner who’s in and out in less than an hour probably didn’t do a good job.

— Many quality ductwork cleaners use truck-mounted, outside vacuum systems that contain dust and debris outside the house.

— Ask whether they follow the standards set by the National Air Duct Cleaners Association.