Bathroom Extractor Fan Regulations

Whether you're installing a brand new ventilation system throughout your whole house or you're just remodelling your bathroom, the type and size of extractor fan you choose for your bathroom can affect the smell and moisture level in the room.

Bathroom ventilation and bathroom extractor fans are required in most building codes, so you must install one in each bathroom to be up to code.

The Fan Must Be Labeled

Any bathroom extractor fan you buy and install in your bathroom should have a label stating that it has been inspected and tested by the Underwriter's Laboratory or a similar testing agency, according to the City of San Jose, California Building Division. The Underwriter's Laboratory label features a UL. Fans with a testing agency label are typically also listed. Testing agencies, like the Underwriter's Laboratory, help keep the consumer from getting faulty extractor fans which could negatively impact their homes.

You Must Use the Appropriate Size Fan

Whether you have a large bathroom or a small one, use the right size extractor fan for your bathroom based on the local building code. A bathroom fan must carry at least 20 cubic feet per minute (cfm) all the time and 50 cfm intermittently, according to the Healthy House Institute. A bathroom extractor fan's projected cfm rate is usually stated on the outside of the packaging.

The Fan Must Duct to the Outside

According to Tim Carter at Ask the Builder, the ducts for bathroom ventilation from the extractor fan must run to the outside. In the past, bathroom fans were often ducted to the attic or other hidden spaces, but this can cause moisture from the bathroom to build up inside your home and create mould and other problems. When you attach you duct to the outside of your home, ensure the edge of the duct is sealed properly so moisture won't sneak into your home from an unexpected spot.