Duct Exhaust Fan In Attic

You mount a switch in each bathroom.

Duct exhaust fan in attic.

The best exhaust fan venting is through smooth rigid ducts with taped joints and screwed to a special vent hood. But more importantly insulating duct work wherever ducts run through unheated parts of the home will help prevent air loss through the thin metal ducts. An external thermostat mounted in the attic controls the temperature and kicks the fan on when the temperature raises to the set limit. 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.

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. Bathroom vent fan ductwork insulation. 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. 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.

In order for attic exhaust fan to be effective you need a supply of fresh air coming in from soffits under the roof s overhang or gable vents. Although this isn t always possible in attic crawl spaces you should always insulate the duct to prevent condensation problems. Look for the special fans starting at 160 at heating cooling equipment. The reason exhaust pipes are insulated in unconditioned spaces your attic is because they carry warm and moist air from your home to outside.

No it s never a good idea to have any exhaust fan in your home dump all that hot moist air in your attic. Insulate the bathroom exhaust vent fan ducts. Because the fan is in the attic you ll hardly hear it. If this pipe is not insulated the heat carried in the air transferred to the pipe will cause condensation and potentially cause water damage at your ceiling or in your attic.

In un conditioned space such as an attic where otherwise your fan duct will be exposed to cold attic air in winter use insulated solid metal ducting or insulated flex duct. Duct already wrapped in insulation at home centers. You can find 4 in. If your attic is enclosed california s building code states it should have cross ventilation.

Like other duct systems in the home insulation around range hood ducts reduces nuisance noise and vibration when the fan inside the vent hood is running. A grille in each bathroom attaches to ducts which then fasten to a y connector at the fan. A single exhaust exits through the roof figure a. Otherwise you re inviting a moisture mold rot insect problem in the building.