Dave Hoh's Home Comfort & Energy Experts Case Studies: Bathroom fan improperly vented into attic, in Ocean Gate, NJ

Challenge

Here in Ocean Gate, NJ, hot or cold weather is no stranger to us, so it’s extremely important to keep moisture out of our attics.  A bathroom fan that is installed without proper duct work to ventilate the moisture outside can destroy your attic or roof.  When warm humid air hits cold attic surfaces it condenses into water.  This moisture can decay roof sheathing and rafters as well as contribute to mold growth.

Solution

The proper solution for an improperly vented bathroom fan is to terminate the fan to the exterior through an insulated duct, with a good back draft damper to an exterior hood with a bug screen.  It’s also important to consider the length and route of duct to reduce air flow restrictions.

This solution will eliminate the unwanted moisture from leaking into the attic that is causing mold and roof rot.  FYI, new construction codes require bath fans to be vented to the exterior as described above.