Two systems that never connect
Your heating and cooling ductwork is a network of supply and return ducts running to registers in each room. Your dryer vent is a single duct from the back of the dryer to a hood on an outside wall or the roof. The 2021 International Residential Code requires the dryer exhaust to be independent of all other systems, so the two should never meet.
| Question | Air ducts | Dryer vent |
|---|---|---|
| What it is | Supply and return ducts for your heating and cooling system | One duct from the dryer to an outside hood |
| What builds up | Dust and debris, and sometimes mold or pests | Lint carried out of the dryer with warm, damp air |
| Why clean it | Visible mold in hard ducts, vermin, or debris coming out of the registers (EPA) | Failure to clean is the leading factor in residential dryer fires, at 34% (U.S. Fire Administration, 2008–2010 data) |
| How often | Only as needed, not routinely (EPA) | Once a year, or sooner if drying slows down (NFPA) |
Does air duct cleaning include the dryer vent?
No, not unless it’s quoted too. Duct cleaning covers the heating and cooling ductwork. The dryer vent is a different duct with a different job, so ask for it by name.
If a duct cleaning company throws in a “free dryer vent,” ask what that includes: the full run from the dryer to the outside hood, or just the hose behind the machine.
“Dryer air duct cleaning” usually means the dryer vent
People search for “dryer air duct cleaning,” “dryer duct cleaning” and “dryer vent duct cleaning.” They usually mean the dryer vent: the duct that carries lint out of the house.
That’s the one with the fire risk, and NFPA recommends cleaning it once a year, or sooner if clothes take longer than normal to dry.
Doing both in one visit
If your ducts meet one of the EPA’s reasons for cleaning and your dryer vent is due, it makes sense to handle both at once. Ask us to quote them together.