Duct Cleaning
What is Duct Cleaning?
Most people are now aware that indoor air pollution is an issue of growing concern and increased visibility. Many companies are marketing products and services intended to improve the quality of your indoor air. You have probably seen an advertisement, received a coupon in the mail, or been approached directly by a company offering to clean your air ducts as a means of improving your home's indoor air quality. These services typically -- but not always -- range in cost from $450 to $1,000 per heating and cooling system, depending on the services offered, the size of the system to be cleaned, system accessibility, climatic region, and level of contamination.
Duct cleaning generally refers to the cleaning of various heating and cooling system components of forced air systems, including the supply and return air ducts and registers, grilles and diffusers, heat exchangers heating and cooling coils, condensate drain pans (drip pans), fan motor and fan housing, and the air handling unit housing (See diagram).
If not properly installed, maintained, and operated, these components may become contaminated with particles of dust, pollen or other debris. If moisture is present, the potential for microbiological growth (e.g., mold) is increased and spores from such growth may be released into the home's living space. Some of these contaminants may cause allergic reactions or other symptoms in people if they are exposed to them. If you decide to have your heating and cooling system cleaned, it is important to make sure the service provider agrees to clean all components of the system and is qualified to do so. Failure to clean a component of a contaminated system can result in re-contamination of the entire system, thus negating any potential benefits. Methods of duct cleaning vary, although standards have been established by industry associations concerned with air duct cleaning. Typically, a service provider will use specialized tools to dislodge dirt and other debris in ducts, then vacuum them out with a high-powered vacuum cleaner.
In addition, the service provider may propose applying chemical biocides, designed to kill microbiological contaminants, to the inside of the duct work and to other system components. Some service providers may also suggest applying chemical treatments (sealants or other encapsulants) to seal or cover the inside surfaces of the air ducts and equipment housings because they believe the sealant will control mold growth or prevent the release of dirt particles or fibers from ducts. These practices have yet to be fully researched and you should be fully informed before deciding to permit the use of biocides or sealants in your air ducts. They should only be applied, if at all, after the system has been properly cleaned of all visible dust or debris.
Indoor Environments Division (6609J)
Office of Air and Radiation (OAR)
EPA-402-K-97-002, October 1997
Choosing a Duct Cleaner
In recent years millions of Americans have had their home air conditioning systems and ductwork cleaned. Duct cleaning can help to reduce the levels of dust within a home, increase the efficiency of the air conditioning system, and diminish the risks of indoor air pollution.
The National Air Duct Cleaners Association (NADCA), a non-profit organization, has published a guideline for consumers to follow When choosing an air duct cleaning company.NADCA offers these suggestions for selecting an air duct cleaner:
- Make sure the cleaning contractor uses "source removal" cleaning methods designed to extract the debris within your air conditioning system. The routine application of encapsulants to seal debris within ductwork is not recommended.
- Get references from past jobs. Ask the duct cleaners customers if they were happy with the services performed, if they felt they benefited from the cleaning, and if they experienced any problems with their air conditioning system after the job.
- See if the duct cleaning company is a member in good standing of your local Better Business Bureau.
- Make sure the duct cleaner has worked on air conditioning systems similar to your own and ask how long the cleaning technicians who will be servicing your system have been performing duct cleaning.
- Make sure the duct cleaner takes care to protect your home and belongings. Duct cleaning is a relatively routine process and you should not have to do any unusual house cleaning after the job.
- Make sure that any chemicals used in the cleaning process are EPA registered for the intended application. You may also request a Material Safety Data Sheet (MSDS).
- Make sure that the cleaner you choose agrees to perform the cleaning services in accordance with all provisions of the industry performance standard NADCA 1992-01, Mechanical Cleaning of Non-Porous Air Conveyance System Components.
- Ask if the firm has all of the necessary business and professional licenses. Some states have recently passed statutes which require that air duct cleaners hold air conditioning contractors' licenses or similar professional licenses.
- Watch out for "add-on" sales. Some cleaners will charge a base fee and then surprise the customer with additional costs for applying sanitzers or other related services. Make sure you have agreed on the total cost and scope of the job before work begins.
- Confirm that the duct cleaner is a member in good standing of the National Air Duct Cleaners Association. Choosing a NADCA member to perform the work will ensure that your facility receives a thorough source removal cleaning in accordance with the association's mandatory performance standard.
Contact the NADCA at:
1518 K Street, N.W., Suite 503, Washington, DC 20005; (202) 737-2926. The association provides free literature and listings of member firms.