Bathroom Duct To Attic Vent

The bathroom exhaust ventilation fan disperses air through an opening in the fan housing which is usually 3 inches in diameter and ideally faces in the direction of the ventilation system outlet.

Bathroom duct to attic vent.

A 3 or 4 inch duct connects to the outlet on the fan housing and runs to a side wall or to the roof and connects to a vent cap that allows the exhaust to disperse outdoors. 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. Do not simply terminate a bath vent fan duct in an attic as shown in our photo above nor can you just dump the exhaust vent into a crawl space nor into a closed wall floor or ceiling cavity. Mount the fan high on the wall to better capture warm moist air.

Options for venting a bathroom exhaust fan include best to worst. Fabricate the duct run from rigid metal or pvc material. Start in the attic and drill a hole through the roof in the desired vent location. Now where the discharge point is is going to be up to you.

That will take it from the bath exhaust fan to a discharge point. One in line centrifugal fan can be mounted in the attic to exhaust the moisture from two bathrooms. Ask your hvac contractor about fabricating a duct run that extends from a fan mounted in a bathroom wall down through the floor and between floor joists out to an exterior wall. Leave the drill bit sticking through the roof so you can find the hole.

Try to keep it close to the fan location. So what you want to do is you want to install a duct a vent duct and you can use flex duct for this. Otherwise you re inviting a moisture mold rot insect problem in the building. The exhaust vent must terminate outdoors.

Each bathroom has its own exhaust fan. A lot of options. Through the roof or an exterior gable wall. Each fan vents separately out the roof.