How To Vent Bathroom Fan Through Attic

Options for venting a bathroom exhaust fan include best to worst.

How to vent bathroom fan through attic. 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. The building code requires a bathroom exhaust fan to vent outside the building so installation of a new bathroom fan necessarily involves installation of ductwork. Flex duct routing details. In attic seal holes in fan housing with foil duct tape.

Depending on the location of the bathroom it may be easy to vent the exhaust fan through the roof. Since you cannot vent a bathroom exhaust fan into the attic what are your options. A grille in each bathroom attaches to ducts which then fasten to a y connector at the fan. Look for the special fans starting at 160 at heating cooling equipment dealers.

Connect the flexduct to the fan itself using plastic ties or second best duct tape. Use rigid metal ducting aluminum or galvanized steel with lengthwise seams facing up and joints sealed with foil tape or duct mastic or rigid plastic pipe. This system is quiet too. This is much easier to do if you have attic access because if you don t you usually have to remove some ceiling drywall and run the ducts along a joist.

It is because of this that many builders tend to advise against this method. The correct way to vent a bathroom fan through an attic is to terminate the vent either to the roof or to the gable wall. The best way to do it is to give the bathroom exhaust fan its own direct vent to the outside of your home and not into the attic where it can mix with the air causing the issues mentioned above. Through the roof or an exterior gable wall.

Because the fan is in the attic you ll hardly hear it. If you vent through a soffit where attic vents are often located the moisture will get sucked back up into the attic or roof venting. You mount a switch in each bathroom. Use foil duct tape to attach flexible duct to connector protruding from the wall cap.

In order to accomplish this the roof has to have a hole cut in it. Long sloppy bending flexduct runs significantly reduce the performance of the vent fan. If you are using flexible fan duct stretch the flexduct tight to keep it as straight and smooth inside as possible.