How often should you clean your air ducts?

"It had been years (if ever) since the air ducts in our house had been cleaned." (Photo courtesy of Angie’s List member Alisa R. or Palatine, Ill.)

"It had been years (if ever) since the air ducts in our house had been cleaned." (Photo courtesy of Angie’s List member Alisa R. or Palatine, Ill.)

Many homeowners who've worked with reputable air duct cleaning contractors are often pleased with the results. While experts generally agree that scientific evidence is lacking to prove that duct cleaning has a direct and significant benefit, they do agree that there is some benefit to having the service performed. Certain conditions warrant having a professional clean the ducts in your home, so here's how to tell if you're overdue for an appointment.

What to look for

The Environmental Protection Agency (EPA) recommends cleaning air ducts when:

  • you suspect that mold exists in the ducts
  • you notice a vermin infestation somewhere in the home, or you see insects or rodents entering or exiting ductwork
  • you see a visible "poof" of dust released from the supply registers when cooled air is exiting the vents

Growing evidence for servicing ducts

While the EPA has conducted several studies to reach their recommendations, other governmental bodies are also participating in studies to determine the effectiveness of cleaning air ducts. The Canada Mortgage and Housing Corporation (CMHC) is one such body, and their findings conclude that:

  • Duct cleaning is beneficial for reducing the amount of dust on the surface of return-air ducts only and not necessarily supply-air ducts.
  • Cleaning air ducts results in a lower concentration of microorganisms such as mold and bacteria.
  • Best practice involves cleaning the return-air ducts only and the air handler/furnace fan to boost air circulation.

How often to clean ducts

Most certified duct cleaners and other experts agree on some general recommendations for how often to have ducts cleaned. You should schedule a duct cleaning appointment:

  • every three to five years. Be wary of a contractor who suggests more frequent cleanings.
  • when you move into a new home, unless you know that the previous homeowner serviced the ducts within the last three years or less.
  • after building a new home.
  • after completing a home remodeling project. Construction projects spread sawdust throughout the home, and unless you go to lengths to protect the ducts, the dust will extend into the ductwork, too.
  • if home occupants have severe allergies. While studies haven't proven a significant connection between health and duct cleaning, anecdotal evidence and comfort may prompt you to proceed with the cleaning.
  • if you have many pets in the home that shed fur and dander or even if you have just one animal that sheds a great deal. Duct cleaning and effective home cleaning practices can help to prevent it from spreading throughout the home.

The best way to determine how often to schedule an appointment for cleaning air ducts involves looking at the needs of your family and the activities that are going on in your life. Further, many folks opt for duct cleaning simply because it makes sense that dust on the surfaces of your home also reaches into the deep crevices of the ducts.

While the jury's still out on a definitive position about duct cleaning, the critical factor to keep in mind is the importance of hiring a reputable professional. Opt to work with a duct cleaner who holds membership with the National Air Duct Cleaners Association (NADCA), the only organization that exists to serve the duct cleaning industry and protect consumers from fraudulent contractors.

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