Bath Fan Vents Into Attic

No you should not vent a bathroom fan directly into an attic.

Bath fan vents into attic. It s all outdoor air anyways right. 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. However you can vent a bathroom fan through an attic while it terminates on the roof or gable end. Second during cold winters you ll be blowing warm moist air onto a cold surface the roof vent and roof plywood.

Bathroom fan vent code requirements include no venting to attic areas to help reduce mold or structural problems. 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. Through the roof or an exterior gable wall. The exhaust vent must terminate outdoors.

No you cannot vent your bathroom exhaust fan into the attic. 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. You should never exhaust the bathroom fan directly into the attic. 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 ventilation codes require a bathroom exhaust fan to vent to the exterior not the attic for health and structural reasons. It seems like such an easy solution just leave a bathroom vent hose in an attic.