Bathroom Exhaust Fan Into Attic

The bathroom here is below an accessible attic so tom ran the exhaust duct across the attic and out a gable end.

Bathroom exhaust fan into attic.

A bird s nest in a bathroom vent will greatly reduce or eliminate the effectiveness of a bathroom exhaust fan. You d often blow air from one bathroom into the other and local building inspectors wouldn t approve it. Bathroom exhaust fans perform an important function by removing excess moisture from your home. It is because of this that many builders tend to advise against this method.

Depending on the location of the bathroom it may be easy to vent the exhaust fan through the roof. This article describes routing bath exhaust fan duct upwards through an attic or roof space or downwards through a floor or crawl space. But while you can t have two fans with one vent you can make one fan and one vent serve two bathrooms. Bathroom vent fans are rated by how many cubic feet of air they can move in one minute known as the cfm rating.

In all cases the ducting needs to conduct the exchaust to the building exterior and needs to terminate in an animal proof vent cover. This involves running ductwork from the fan usually though an attic and out through the roof. All municipalities have different requirements but some do not draw a hard line on requiring exhaust fans. This setup requires an in line centrifugal fan mounted in the attic drawing air simultaneously from both bathrooms see photo.

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 ventilation fan duct routing routing a bath vent duct down out or up through an attic or roof out. To determine which size fan to buy for your bath multiply the room s square footage by 1 1. Bathroom code does address the issue of moving odor and moisture laden air from the bathroom to the outside.

No you cannot vent the bathroom exhaust fan into the soffit vents. Bathroom ventilation codes require a bathroom exhaust fan to vent to the exterior not the attic for health and structural reasons. Can you vent a bathroom exhaust fan into the soffit vents. It s also important to note that if you install a roof vent cover for a clothes dryer you must remove the metal screen because it will catch lint and may turn into a fire hazard.

Bathroom fan vent code requirements include no venting to attic areas to help reduce mold or structural problems.