Air Duct Cleaning in the Pacific Northwest: When It Makes Sense

What the EPA says

The U.S. Environmental Protection Agency has long said that duct cleaning has never been shown to prevent health problems, and that there is little evidence that cleaning only the ducts will improve how efficiently your heating and cooling system runs. It does not recommend routine cleaning, and says a light amount of household dust in the ducts is not known to be a health risk.

The EPA does say you should consider having ducts cleaned if:

• there is substantial visible mold growth inside hard-surface ducts or on other parts of the system,
• the ducts are infested with rodents or insects, or
• the ducts are clogged with excessive dust and debris, and particles are being released into your home from the supply registers.

If a company tells you the EPA recommends routine duct cleaning, or promises health benefits, treat that as a red flag.

When it is reasonable to clean your ducts

• After a renovation or construction that left drywall dust, sawdust or debris in the system.
• After a pest problem, such as mice or insects in the ducts.
• If you can see mold in the ducts or on parts of the system. The moisture problem that caused it must be fixed first, or the mold will return. Wet or moldy insulated ducts usually cannot be cleaned and may need replacing.
• If you can see heavy dust or debris coming from the vents, or a persistent musty or burning smell when the heat comes on.
• If you are moving into a home and an inspection shows heavy buildup.

If your ducts are clean and you see none of these signs, cleaning is probably unnecessary. It is normal for return registers to collect dust, and the registers can be vacuumed or wiped.

What helps more than duct cleaning

• Change your furnace filter on schedule, and use the filter grade your system is built for.
• Keep moisture under control. Fix leaks quickly and keep indoor humidity in a healthy range.
• Keep dirt from getting in. Seal gaps, keep the area around the furnace clean, and use doormats and a no-shoes habit.
• Clean carpets and rugs on a schedule, so soil does not build up in your home. See our guide to spring pollen in carpets, rugs and ducts.

If you have a leak, flood or mold, that is a restoration problem, not a duct cleaning job.

If you decide to have ducts cleaned

• Ask the company to show you what they find, with photos or a camera, before and after.
• Ask whether they clean the whole system, including the registers, the main trunk lines and the blower area, and not just the vents.
• Ask for a written quote that lists exactly what is included, and compare more than one.
• Be careful about add-on sprays, sealants and biocides. The EPA advises that these should only be applied, if at all, after the system is properly cleaned, and with caution.
• Check licensing, insurance and references.

You can read the EPA guide yourself: Should You Have the Air Ducts in Your Home Cleaned?

How we approach it

We inspect first and show you what we find. If your ducts do not need cleaning, we will say so. See our air duct and dryer vent cleaning page for what the service includes. Dryer vents are a separate matter, since lint buildup is a fire risk and does need regular attention.