Why Your Bathroom Exhaust Fan Might Not Be Working

The Tissue Test

Hold a single-ply tissue or a small piece of toilet paper near the exhaust grate with the fan running. If the tissue is pulled firmly against the grate and stays there, the fan is creating adequate airflow. If the tissue flutters weakly or falls away, the fan is not pulling enough air to be effective. This 10-second test catches the most common exhaust fan failures.

Common Failures

The fan may vent into the attic or ceiling cavity instead of outdoors. The duct may be disconnected, crushed, or blocked. The fan motor may have weakened with age. Or the fan may be undersized for the bathroom. In each case, shower moisture stays in the bathroom and migrates to adjacent rooms, raising humidity and creating conditions for mold growth. This is one of the most common and most fixable air quality issues in residential homes.