Exhaust Into Attic

The reason you don t vent into the attic is because when the attic is colder than the vent air moisture will condense inside the attic space causing mold and other problems.

Exhaust into attic.

Dumping bathroom exhaust into an attic or under roof space invites costly mold contamination frost under the roof in freezing climates moisture damage to roof sheathing possibly even plywood delamination or rot roof failures and shorter roof shingle life. In either case do not vent into the wall or the 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. Small diameter ducts could trap grease creating a fire hazard.

All municipalities have different requirements but some do not draw a hard line on requiring exhaust fans. The duct for your exhaust fan needs to be run to the outside of the house to remove the chance of a fire hazard. If you re tempted to vent your exhaust fan through an existing roof vent or even vent it into the attic don t do it. The kitchen vent fan must exhaust directly to the outside not into an attic crawlspace or a space between floors.

Step 2 run the ducts. Your vent hood will have places available for either attic or wall exhaust. Cover the hole that you are not using for exhaust and secure the hood to its. You can find 4 in.

The duct should be smooth and straight with as few bends as possible. Surprisingly bathroom fans are not required by some building codes. The fan s installation instructions should specify the diameter of the duct. Bathroom code does address the issue of moving odor and moisture laden air from the bathroom to the outside.

It may also violate a shingle warranty. This can be a serious problem in cold weather if the living space is not properly sealed off from the attic. Options for venting a bathroom exhaust fan include best to worst. First you ll partially block your roof vent with the piping reducing the flow of cooling air through your attic.

Bathroom exhaust fans perform an important function by removing excess moisture from your home. When we got into the attic i quickly noticed the smell moisture and what i could see as mold on the roof rafters above each bathroom. Taking advantage of this natural process referred to as passive ventilation is the most common way to vent an attic.