Bathroom Vent Fan Venting Into Attic

When venting a bathroom exhaust fan make sure to vent the air to the outside rather than into your attic where it can cause mold and mildew to form.

Bathroom vent fan venting into attic.

Bathroom ventilation codes require a bathroom exhaust fan to vent to the exterior not the attic for health and structural reasons. This involves running ductwork from the fan usually though an attic and out through the roof. Options for venting a bathroom exhaust fan include best to worst. It seems like such an easy solution just leave a bathroom vent hose in an attic.

No you should not vent a bathroom fan directly into an attic. Do not simply terminate a bath vent fan duct in an attic as shown in our photo above nor can you just dump the exhaust vent into a crawl space nor into a closed wall floor or ceiling cavity. Your attic is not a temperature controlled environment is never the same temperature as your living space and generally closer to the temperature outside. Through the roof or an exterior gable wall.

The exhaust vent must terminate outdoors. Depending on the location of the bathroom it may be easy to vent the exhaust fan through the roof. Surprisingly bathroom fans are not required by some building codes. However you can vent a bathroom fan through an attic while it terminates on the roof or gable end.

You should never exhaust the bathroom fan directly into the attic. It is because of this that many builders tend to advise against this method. In order to accomplish this the roof has to have a hole cut in it. Bathroom code does address the issue of moving odor and moisture laden air from the bathroom to the outside.