Choosing an air-duct cleaning service
First, check the ducts , using a mirror and a flashlight. If there are no large deposits of dust or mold, or if no one in the house suffers allergies or asthma, you probably don't need to have the air ducts cleaned, says the U.S. Environmental Protection Agency. Just because you have dirty return registers doesn't mean you have disgusting ducts. It's normal for dust-laden air to be pulled through the grates, which you can vacuum yourself. Do have your ducts cleaned if:
Check the cleaner's equipment. Be wary of a company that uses only shop-vac-size machines with 2-inch hoses. Talk to at least three companies, and make sure the one you choose uses powerful gasoline-powered machines mounted to trucks. Hoses should be at least 10 inches in diameter, similar to a dinner plate. Otherwise you're just stirring stuff out of the ducts without removing it, which will create more damage.
The cleaning service should:
For more information: The National Air Duct Cleaners Association, http://www.nadca.com/, has instructions on what to look for and how to locate a duct cleaner. Additional information also can be found at the EPA Web site, http://www.epa.gov/, by searching for "air ducts."