Bath Fan Vents Into Attic

It seems like such an easy solution just leave a bathroom vent hose in an attic.

Bath fan vents into attic. Bathroom ventilation codes require a bathroom exhaust fan to vent to the exterior not the attic for health and structural reasons. The exhaust vent must terminate outdoors. Your attic is not a temperature controlled environment is never the same temperature as your living space and generally closer to the temperature outside. No you cannot vent your bathroom exhaust fan into the attic.

Through the roof or an exterior gable wall. First you ll partially block your roof vent with the piping reducing the flow of cooling air through your 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. No you should not vent a bathroom fan directly into an 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. Otherwise you re inviting a moisture mold rot insect problem in the building. Second during cold winters you ll be blowing warm moist air onto a cold surface the roof vent and roof plywood. However you can vent a bathroom fan through an attic while it terminates on the roof or gable end.

Bathroom fan vent code requirements include no venting to attic areas to help reduce mold or structural problems. If you re tempted to vent your exhaust fan through an existing roof vent or even vent it into the attic don t do it.