Bathroom Exhaust Fan Vented Into Attic

Bathroom exhaust fans perform an important function by removing excess moisture from your home.

Bathroom exhaust fan vented into attic.

Note that the bathroom vent fan must always exhaust to the outdoors. This article describes routing bath exhaust fan duct upwards through an attic or roof space or downwards through a floor or crawl space. You d often blow air from one bathroom into the other and local building inspectors wouldn t approve it. But while you can t have two fans with one vent you can make one fan and one vent serve two bathrooms.

Never allow the duct to simply blow into an attic crawlspace or other enclosed area. Bathroom ventilation fan duct routing routing a bath vent duct down out or up through an attic or roof out. Bathroom ventilation codes require a bathroom exhaust fan to vent to the exterior not the attic for health and structural reasons. If you vent the bathroom exhaust fan to close to the soffit vents which are vented plates under your homes outer edge and roof your home the air can be sucked right back into the attic from the soffit.

In all cases the ducting needs to conduct the exchaust to the building exterior and needs to terminate in an animal proof vent cover. No you cannot vent the bathroom exhaust fan into the soffit vents. I would by lying if i told you that it will cause problems it may be totally fine. This setup requires an in line centrifugal fan mounted in the attic drawing air simultaneously from both bathrooms see photo.

The truth about attic bathroom venting. 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. Also the installation of the bathroom exhaust fan will go much quicker if you ask a spouse or friend to help be in the attic while you work from below or to hand you tools while you re on. Bathroom fan vent code requirements include no venting to attic areas to help reduce mold or structural problems.