In Attic Bathroom Exhaust Fan

Each bathroom has its own exhaust fan.

In attic bathroom exhaust fan.

Condensate may also be dripping off the exterior surface of the vent duct in attic or crawl space. It s all outdoor air anyways right. 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.

Both bathrooms are vented by a single in line fan that has one exhaust vent running through the roof. However you can vent a bathroom fan through an attic while it terminates on the roof or gable end. Several different ways you can move that hot air to the outside. Air vent 18 inch dia electric gable vent fan courtesy of home depot.

Bath exhaust is almost always warm and this air will float up and into the soffit ventilation openings. No you should not vent a bathroom fan directly into an attic. It s perfect for reducing cooling costs as it pulls fresh air from outside and expels warm attic air out through the exhaust vents. One in line centrifugal fan can be mounted in the attic to exhaust the moisture from two bathrooms.

No it s never a good idea to have any exhaust fan in your home dump all that hot moist air in your attic. It seems like such an easy solution just leave a bathroom vent hose in an attic. Bath exhaust is almost always warm and this air will float up and into the soffit ventilation openings. In those areas ventilation in bathrooms is required but it can be from a window or fan your choice.

Section 1203 4 2 1 of california s building code requires all bathrooms with a bathtub shower spa or similar fixtures to be ventilated by an exhaust fan. 2 moisture droplets dripping from the exhaust fan or ducting. All municipalities have different requirements but some do not draw a hard line on requiring exhaust fans. Most roof overhangs today have continuous soffit ventilation strips.

You ve now put the water right back up into the attic without realizing it. Your attic is not a temperature controlled environment is never the same temperature as your living space and generally closer to the temperature outside. As warm moist air moves through a fans vent system in the attic the duct often become cooler especially in the winter thus condensate may form and drip back down through the fan itself. Each fan vents separately out the roof.

You ve now put the water right back up into the attic without realizing it. Surprisingly bathroom fans are not required by some building codes.