Here's one less thing you have to regularly clean -- ducts.

There's growing evidence duct cleaning may be a solution in search of a problem rather than cure for what ails the air in your home.

Consumer Checkbook (subscribers only) research released this year says the dust you see in your ventilation ducts pretty much stays where it is. It likely won't become airborne unless disturbed -- say by duct cleaning. Under most circumstances duct dust is inert and harmless.

Federal and private health officials back up Checkbook -- an independent operation that rates services much like Consumer Reports rates goods -- and stop short of recommending against duct cleaning, but they also do not endorse the work as routine maintenance.

"Should You Have Your Air Ducts Cleaned?" the latest U.S. Environmental Protection Agency information on the subject says succinctly, "Duct cleaning has never been shown to actually prevent health problems. Neither do studies conclusively demonstrate that particle (e.g. dust) levels in homes increase because of dirty air ducts. This is because much of the dirt in air ducts adheres to duct surfaces and does not necessarily enter the living space."

Likewise, a Canada Mortgage and Housing Corporation report includes before and after duct cleaning test results from 33 homes in Montreal. It found no significant air quality or energy efficiency improvements. In some cases, particle levels increased immediately after a duct cleaning job. In other cases, particle levels went down after the cleaning but returned to previous levels within weeks.

Research also has not scientifically demonstrated the effectiveness of chemical biocides, "sealants" and other duct applications cleaning service provides may offer.

There are no chemical biocides registered by the EPA for use in internally-insulated air duct systems.

The EPA does recommend servicing for fuel burning furnaces, stoves or fireplaces before each heating season to protect against carbon monoxide poisoning. And you should regularly have fireplace and wood burning appliance fire boxes and flues cleared of potentially flammable sooty deposits and creosote, the by-products of incomplete combustion.

The EPA only recommends duct cleaning if:

• Ducts are infested with vermin (including rodents or insects), in which case you may also need a licensed pest control operator.

• Ducts are clogged with excessive amounts of dust and debris and/or particles that are actually released into the home.

• There is substantial visible mold growth inside hard surface (sheet metal) ducts or on other components of your heating and cooling system. Beware of important considerations about mold detection in heating and cooling systems.

• Many sections of your heating and cooling system may not be accessible for a visible inspection, so ask the service provider to show you any mold he or she says exists.

• A positive determination of mold's existence can be made only by a certified microbiology expert and that may require laboratory analysis for final confirmation.

• If you have insulated air ducts and the insulation gets wet or moldy it cannot be effectively cleaned and should be removed and replaced.

• If moisture is allowed to remain for more than 48 hours or other conditions causing mold growth are not corrected, mold will return.

  If you decide to go ahead and hire a duct cleaner, follow these EPA recommendations.

• Consider hiring National Air Duct Cleaners Association (NADCA) members who are locally regulated, licensed or certified. Talk to at least three different service providers, get written estimates and only then decide if you want your ducts cleaned. When the service providers arrive have them show you the contamination that would justify having your ducts cleaned.

• Whenever possible, check duct cleaners' references with other customers and with local or state consumer protection authorities or the Better Business Bureau for complaints.

• Don't hire duct cleaners who make sweeping claims about the health benefits of duct cleaning, who say you need routine duct cleaning or who say they are certified by the EPA or other government agency. The EPA does not establish standards for, certify, endorse or approve duct cleaning companies.

• Do not allow anyone to use chemical biocides or sealants without a thorough understanding of the pros and cons outlined in "Should You Have Your Air Ducts Cleaned?"

• Get a written agreement outlining the total cost and scope of the job before work begins. Don't sign anything you don't understand.

Published: July 10, 2008

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Broderick Perkins parlayed a career in old-school journalism into a contemporary digital news service that really hits home. The award-winning consumer journalist, originally from Wilmington, DE, is founder, publisher and executive editor of the bootstrap DeadlineNews Group, a Silicon Valley-based editorial content and consulting service specializing in residential real estate, consumer news and related editorial consulting services. The DeadlineNews Group includes the website, DeadlineNews.com, offering real estate editorial content and consulting services, and its back shop, the Deadline Newsroom, an open house on news that really hits home. Perkins obtained his formal journalism education from University of Delaware and a journalism boot camp, the Institute of Journalism Education at the University of California-Berkeley. He went on to 20 years of service as a daily newspaper journalist at the Wilmington, DE News Journal and San Jose, CA Mercury News. Perkins covered housing on the San Jose Mercury News reporting team which earned a General News Reporting Pulitzer Prize in 1989 for coverage of the Loma Prieta earthquake. He has also produced real estate, consumer and small business content for the Wall Street Journal, Los Angeles Times, RealtyTimes.com, Nolo.com, Better Homes and Gardens, the National Association of Realtors, Homestore/Move and Intuit/Quicken among more than three dozen publications. In addition to managing the DeadlineNews Group, Perkins most recently served as chief editorial consultant for Nolo's Essential Guide To Buying Your First Home, Nolo, and writes real estate television scripts for RealtyTimes.com.