Bathroom Exhaust Fan Goes Into Attic

This section notes that air exhausted from the bathroom must be sent outdoors not indoors to the same residence or indoors to any other dwelling unit.

Bathroom exhaust fan goes into attic.

Proper bath fan exhaust. Mold can spread rapidly in an attic. In order to accomplish this the roof has to have a hole cut in it. For optimum performance locate it between the shower and the toilet.

It is because of this that many builders tend to advise against this method. No you cannot vent your bathroom exhaust fan 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. Climb into the attic and clear away any insulation from around the hole.

However you can vent a bathroom fan through an attic while it terminates on the roof or gable end. Draw a mark on the bathroom ceiling where you d like to install the vent fan. Use an extra long 3 8 inch diameter spade bit to bore a reference hole through the ceiling and into the attic. It may also violate a shingle warranty.

One attic mounted fan for two bathrooms one in line centrifugal fan can be mounted in the attic to exhaust the moisture from two bathrooms. It s all outdoor air anyways right. While this may seem obvious homeowners may out of convenience direct the vent into either of these locations. Depending on the location of the bathroom it may be easy to vent the exhaust fan through the roof.

Mold is commonly found in attics with bath fans that exhaust moist air into the attic. Several different ways you can move that hot air to the outside. No you should not vent a bathroom fan directly into an attic. You should never exhaust the bathroom fan directly into the attic.

It can cause you a lot of problems with mold and mildew forming on the underside of your rafters and decking as well as getting into your insulation. It cannot move air to a crawlspace or attic. Bath fans should always exhaust outside through the roof via insulated duct and terminate on a dampered roof cap. No it s never a good idea to have any exhaust fan in your home dump all that hot moist air in your attic.

Dumping bathroom exhaust into an attic or under roof space invites costly mold contamination frost under the roof in freezing climates moisture damage to roof sheathing possibly even plywood delamination or rot roof failures and shorter roof shingle life. Click here to learn more about attic mold.