Why Bathroom Fan Vented Into Attic

This article describes routing bath exhaust fan duct upwards through an attic or roof space or downwards through a floor or crawl space.

Why bathroom fan vented into attic.

But while you can t have two fans with one vent you can make one fan and one vent serve two bathrooms. 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. It eliminates the need for routing ductwork through the house and these fans usually dry the bathroom more quickly. This moist air will cause condensation on the surfaces in your attic.

You d often blow air from one bathroom into the other and local building inspectors wouldn t approve it. 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. In all cases the ducting needs to conduct the exchaust to the building exterior and needs to terminate in an animal proof vent cover. Can you vent a bathroom exhaust fan into the soffit vents.

This can not only cause mold but damage to your roof system. Surprisingly bathroom fans are not required by some building codes. No you cannot vent the bathroom exhaust fan into the soffit vents. 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.

In fact i have seen numerous houses that haven t yet had signs of mold with the bath fan venting incorrectly. Bathroom code does address the issue of moving odor and moisture laden air from the bathroom to the outside. Bathroom exhaust fans perform an important function by removing excess moisture from your home. I would by lying if i told you that it will cause problems it may be totally fine.

This involves running ductwork from the fan usually though an attic and out through the roof. Second during cold winters you ll be blowing warm moist air onto a cold surface the roof vent and roof plywood. Venting the fan into the attic can cause many issues because of the moist air the fan removed from the bathroom. 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. Bathroom ventilation fan duct routing routing a bath vent duct down out or up through an attic or roof out. Depending on the location of the bathroom it may be easy to vent the exhaust fan through the roof.