Vent Fan Ducting In Attic

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.

Vent fan ducting in attic.

The remington solar ventilation attic fan is completely the remington solar ventilation attic fan is completely powered by free solar energy. The best exhaust fan venting is through smooth rigid ducts with taped joints and screwed to a special vent hood. You can find 4 in. Duct already wrapped in insulation at home centers.

These ducts should be insulated or replaced with pre fab insulated ductwork or flexduct and a better installation would have shortened that very long duct as much as possible exiting to a soffit closer to the bathroom. If section r303 4 is included but the previous section has been struck through or not included this may mean that your bathroom must have a bathroom fan and that a window cannot be used as a substitute. In all cases the ducting needs to conduct the exhaust to the building exterior and needs to terminate in an animal proof vent cover. Although this isn t always possible in attic crawl spaces you should always insulate the duct to prevent condensation problems.

Bath vent fan duct routing. Bathrooms require exhaust venting fans in some communities this section may be in lieu of section r303 3 or in addition to 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. This article describes routing bath exhaust fan duct upwards through an attic or roof space or downwards through a floor or crawl space.

This setup requires an in line centrifugal fan mounted in the attic drawing air simultaneously from both bathrooms see photo. 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. Up through roof down through floor or crawl area. But while you can t have two fans with one vent you can make one fan and one vent serve two bathrooms.

Our photo above shows a long routing of bath vent fan ducts across an attic floor to an exit at the building soffit or eaves and the condensation of moisture in such vent lines.