What You Need to Know About
Cleaning Air Ducts

By: Andrea Pisani Babich

If you’re like most people, you likely ignore your heating and cooling systems unless you’ve encountered a problem. It’s designed to be inconspicuous.

Tucked behind walls, under floors, and above ceilings, air ducts act are the invisible railway system transporting out pre-conditioned air and delivering back conditioned air into your home. Air ducts, just like the condenser and evaporator coils of your air system, need to be cleaned and maintained.

Cleaning and maintaining your HVAC system has several benefits:

  • More effective heating and cooling, keeping you more comfortable in your home
  • Greater energy efficiency, which saves you money
  • Longer lifespan of your cooling unit with few repairs needed
  • Health benefits for those with asthma, allergies, or compromised immune systems

DIY or Hire?

If you’re a DIYer or even someone who occasionally likes to tackle a job yourself, you can handle some aspects of cleaning and maintaining your heating and cooling system. Cleaning your air ducts is not one of them. Hosing out the condenser coils, vacuuming the inside of the air handler, changing air filters are all simple jobs that don’t typically require specialized skills, but air ducts are different.

Cleaning an air duct requires specialized equipment and training and should only be performed by a licensed HVAC professional.

When to Have Air Ducts Cleaned

If the rest of your heating and cooling system is well maintained, air ducts usually don’t need to be cleaned annually, and every few years should do. But if you notice the following conditions, you should call a professional HVAC service for a thorough cleaning of your air ducts and the rest of your system.

  • Substantial mold appears to be growing inside the ducts or other components of your system. Be aware that not everything that looks like mold is actually mold. A heating and cooling expert can make a final determination upon inspection.
  • Ducts show evidence of animal or insect infestation, which may include droppings, bodily remains, and nests.
  • A nasty odor from your ductwork could indicate the presence of mold, mildew, or animal infestation.
  • Ducts are clogged with excessive amounts of dust and debris.
  • Vents are covered in dust.
  • Dust buildup coats your supply registers or is being released into your home.
  • Ducts have sustained water damage.
Closeup of a dirty air conditioning vent in an old building

Left Mold on the outside of an air vent

Right Debris in a home air duct

Air Ducts Are Just the Beginning of the Cleaning Process

Cleaning the air ducts is only part of the maintenance process. Because the ducts serve as the network between all parts of the air system, all other components must be inspected and cleaned as well to prevent recontamination of the ducts.

A total cleaning process should include an inspection of the air ducts to check for water damage, leaks, excess dust, or debris.

Once the air ducts have been cleaned or pass inspection, other components that affect efficiency and effectiveness will be cleaned. These include—

Air duct cleaning is a multistep process that should take about two to five hours, but is well worth the time and expense to have it done. In some cases of extreme buildup, air duct cleaning can increase efficiency as much as 40%.

How to Keep Your Air Ducts Clean

Preventing dirt and dust from getting into your heating and cooling system in the first place is the best way to keep your air ducts clean. Your first line of defense against HVAC dirt and dust is the air filters that clean the air being pulled in by the air returns.

Cleaning replaceable filters or changing disposable ones at least every three months will help keep dust, pet hair, and dander out of your HVAC system.

Other steps you can take to keep your air ducts clean:

According to the United States Department of Energy, Americans could be wasting 10%–20% of their energy costs on inefficient heating and cooling systems. Increasing efficiency by keeping air ducts and the rest of your system clean and well-maintained can substantially reduce your heating and cooling bills and let you breathe easy.

A very dirty air filter close-up

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