Bathroom fans pull out steam so mirrors don't fog and mold doesn't grow. Kitchen range hoods clear smoke, odors, and heat from cooking. Both should only move air one way: out.
The backdraft damper
At the end of each exhaust duct is a small flap called a backdraft damper. It opens when the fan runs and closes when it stops, so outside air, bugs, and debris stay out.
When it fails
Dirt, lint, nesting animals or a broken hinge can leave the damper stuck open. Then the duct becomes a hole in your house: cold drafts in winter and hot, humid air in summer that your AC has to deal with.
What to check
- A draft or outdoor smell near the fan when it is off
- Condensation or water stains around the fan housing
- A rattling flap on the outside wall or roof cap
- A fan that sounds loud but barely moves air
A damper is a cheap part to replace. If you notice any of these, call us and we will check the fan, the duct, and the damper.
Need a hand with this?
New ducts, repairs, sealing, and cleaning for better airflow.
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