How Often Should You Clean Air Ducts?

Cleaning Air Ducts

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Your home's HVAC system air ducts carry an unbelievable amount of air every day. And with that air, it carries all sorts of debris: dust, spiderwebs, mites, hair, dander, and even microbes and mold spores. Since so much of that debris ends up in the ductwork, how often should you clean your air ducts?

How Often to Clean Air Ducts

Air ducts do not need to be cleaned on a regular schedule. Instead, you should clean your air ducts only when needed, according to the EPA. There are a few conditions that warrant air duct cleaning: visible mold or dirt in the system, rodents or insects, and for residents who have allergies or illnesses.

Cleaning air ducts only on an as-needed basis is mirrored by National Air Duct Cleaners Association (NADCA), a trade group. But NADCA adds that homeowners should have their air ducts inspected once a year to check on the condition of the air ducts.

Homeowners cannot see farther into the ductwork than the last few feet. To see all the way into the ductwork, a video inspection by an air duct cleaning company is necessary.


Even though air ducts don't need to be cleaned on a set schedule, there are no negatives—other than the cost—to having the ducts cleaned regularly.

When Air Ducts Need to be Cleaned

Primary conditions that mean the air ducts should be cleaned include:

  • Visible mold growth
  • Large amounts of dust inside the air ducts
  • Rodents or insects
  • Residents with allergies, asthma, or other illnesses

Secondary conditions include:

  • Smokers in the house
  • Pets that shed a lot of hair or have dander
  • Water contamination to the air ducts
  • Damage to the ducts
  • Recent renovation, especially drywall work


Dust in the first few feet of the return air duct doesn't necessarily mean that the ducts need to be professionally cleaned. Return ducts tend to be dirtier since they pull room air back to the system. They can be cleaned with a vacuum and extension.

Benefits of Clean Air Ducts

The main benefit to having your home's air ducts cleaned is the removal of mold growth. Contaminated air ducts can become a breeding ground for microbe growth, even under normal conditions. Toxigenic mold, or mycotoxins, can be hazardous to residents. Whenever the HVAC system pushes air through the ductwork, mold spores are distributed throughout the home.

If water has entered the ductwork and the moisture wasn't immediately dried up, mold and mildew will likely have developed. So, it's a good idea to clean the ducts after this type of unexpected event. If your home has recently had a major renovation, especially with drywall work or floor sanding, it's also helpful to have the ducts cleaned before the HVAC is turned on.

DIY vs. Professional Air Duct Cleaning

DIY Duct Cleaning
  • End sections of return and supply ducts cleaned

  • Debris moved toward vents

  • Debris in ductwork partially removed

  • $50 to $100

Professional Duct Cleaning
  • Entire ductwork cleaned

  • Debris moved toward HVAC unit

  • Debris in ductwork fully removed

  • $450 to $1,000

Full, system-wide air duct cleaning can only be done by a professional duct cleaning company. The commercial machines used by the companies aren't available to homeowners and cannot be duplicated with consumer-grade vacuums.

With a method often called source removal, commercial machines mechanically agitate the debris and then extract it with a HEPA vacuum, all within a sealed system.

DIY duct cleaning can clean some of the ductwork, mainly the end portions. A vacuum with an extension can reach into the end 2 to 4 feet of the return and supply ducts. The registers (grilles or vents) should be vacuumed, too.

  • What happens if air ducts are not cleaned?

    If mold is growing in the air ducts, mold spores will continue to grow and be distributed throughout the house with each HVAC cycle. Other debris that isn't microbial is less of a health hazard.

  • What are the pros and cons of duct cleaning?

    Pros of duct cleaning are that it removes all debris from the ductwork system and not just the last few feet that can be removed by the homeowner with a vacuum. Other than the cost of duct cleaning, there are no negatives to the service.

  • Why does my house get so dusty?

    Reduce the frequency of air duct cleaning or eliminate it altogether by keeping your house less dusty. Close doors and windows. Use doormats. Vacuum and damp mop floors frequently. Keep pets cleaned and groomed. Change the HVAC filter frequently.