Bathroom Vent Fan Venting Into Attic

Depending on the location of the bathroom it may be easy to vent the exhaust fan through the roof.

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. Through the roof or an exterior gable wall. It is because of this that many builders tend to advise against this method. 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.

Surprisingly bathroom fans are not required by some building codes. In order to accomplish this the roof has to have a hole cut in it. The exhaust vent must terminate outdoors. This involves running ductwork from the fan usually though an attic and out through the roof.

It seems like such an easy solution just leave a bathroom vent hose in an attic. All municipalities have different requirements but some do not draw a hard line on requiring exhaust fans. No you should not vent a bathroom fan directly into an attic. Bathroom ventilation codes require a bathroom exhaust fan to vent to the exterior not the attic for health and structural reasons.

Your attic is not a temperature controlled environment is never the same temperature as your living space and generally closer to the temperature outside. Bathroom code does address the issue of moving odor and moisture laden air from the bathroom to the outside. You should never exhaust the bathroom fan directly into the attic. No you cannot vent your bathroom exhaust fan into the attic.