Duct cleaning has never been shown to actually prevent health problems but the media is full of advertisements promoting cleaning services, many of which apply chemicals to the duct work to kill or control bacteria, fungi and other organisms. EPA experts urge anyone contemplating air duct cleaning to be aware of the facts and get as much information as possible before spending a lot of money.
EPA does not recommend cleaning air ducts unless a specific problem occurs such as clogging or vermin infestation. Studies show that air particles or dust in homes do not increase because of dirty air ducts.
Mold can be an especially tricky problem. If a visible substance appears to be mold, a positive determination can only be made by an expert and may require laboratory analysis. The presence of mold does not necessarily mean that ducts must be cleaned. Keep in mind that internally insulated air ducts that get wet or moldy cannot be effectively cleaned and will require replacement.
No matter what type of ducts you have (unlined sheet metal or fiberglass-lined), the conditions causing mold growth---such as leaking pipes or improper humidity--- must be corrected or mold will reoccur regardless of cleaning or replacement.
If you decide to have your ducts cleaned, talk to at least three contractors and ask detailed questions. Inquire about their experience in duct cleaning and working on systems like yours. Find out what procedures they use to protect residents, pets and homes from contamination. Ask if they comply with the cleaning standards of the National Air Duct Cleaners Association. Find out whether they hold any relevant state licenses and check references. Also contact your local consumer affairs office or Better Business Bureau to learn about any complaints against the company you're considering.
The duct cleaning service may tell you that you need a disinfectant, sanitizer or other antimicrobial agent applied to kill germs and mold and prevent future growth. The company may also want to apply ozone. Be aware that little research has been conducted on the effectiveness of these techniques. In fact, using these products may trigger the very health problems you were trying to avoid. Chemicals sprayed into an operating air control system may be released into the home triggering adverse health effects.
EPA regulates sanitizers, disinfectants and other antimicrobial products under federal pesticide laws. A product must be registered by EPA for a specific use before it can be legally used for that purpose. EPA has assessed the health risks of only some biocide products specifically for use in heating, ventilation and air conditioning (HVAC) systems. Some of the product registrations are only for coatings applied at the point of manufacture and should not be used on existing systems.
If you allow the use of a disinfectant or antimicrobial product in your air ducts, carefully read the label before it is applied. Make sure it has an EPA registration number (EPA Reg#) and states that it can be used specifically in air ducts or HVAC systems. If you have the EPA registration number, you can view the approved product label on the Internet at www.epa.gov/pesticides/pestlabels/ Check the label for very specific directions. The directions should include information about cleaning the system before application, using the correct amount, proper application method and the conditions under which the product can be used. Also read the hazards and precautionary statements. Since the label is the law, make sure the product is used strictly according to its label. As a precaution, all residents and pets should leave the premises during application.
To learn more about air duct cleaning, please see the EPA publication "Should You Have the Air Ducts In Your Home Cleaned?" EPA 402-K-97-002, available on the Internet at www.epa.gov/iaq/pubs/airduct.html or by calling the Indoor Air Quality Information Clearinghouse at (800) 438-4318. For questions regarding antimicrobial products approved for air ducts, contact the Antimicrobial Hot Line at (703) 308-0127.
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CONTACT:
Karen Thompson, (312) 353-8547
For Immediate Release
No. 04-OPA034
CHICAGO (April 15, 2004)