Do I need to have my home's air ducts cleaned regularly?

Few home maintenance questions elicit as much difference of opinion as the need to have air ducts professionally cleaned. The problem centers on the usefulness of such a cleaning if there's no evidence of a dangerous substance inside your duct work, like mold. It's hard to find a homeowner who hasn't gotten a solicitation phone call or flyer about duct cleaning services, some making health claims about their value.

Unfortunately there aren't any studies that support such claims. And the cost of what seems like a good idea, a periodic cleaning, could come as a shock, running in the hundreds of dollars for a service that's unnecessary.

According to the EPA, here are specific circumstances that DO warrant a professional cleaning:

• Visible mold within the metal ducts (if a service person offering an evaluation tells you there's mold, insist on seeing it)
• Evidence of vermin, such as mice that have settled in for the long haul
• Dust and debris that are clogging the works and being released into your home through floor or wall registers

Services that have a much more tangible value and should be done regularly are:

• Heating system maintenance, usually done once a year
• Chimney maintenance, usually done once a year before you use your fireplace; you might be able to get away with a chimney sweep's service every other year if you don't use your fireplace very often
• Wood (or other combustible) burning stove inspection

You can do a lot to improve the air quality in your home by using HEPA filters and changing them every two or three months, depending on how dirty they get. These filters trap particles that could aggravate your airways, especially if you have asthma.

Should you need to hire a duct cleaning service, be sure that workers follow the guidelines of the National Air Duct Cleaners Association. If your ducts are made of fiberglass duct board or insulated inside with fiberglass duct liner, the EPA recommends that the technicians also follow the guidelines of the North American Insulation Manufacturers Association.