What is an Air Admittance Valve (AAV)?

An AAV is a one-way mechanical valve that is installed locally at the site of a plumbing fixture, allowing proper venting to occur without a connection to a larger venting system and stack vent. There are several different AAVs on the market today that all slightly vary in design; however, they each perform the same function.

How Does An Air Admittance Valve Work?

When there is a decrease in pressure, the valve opens to let air into the pipe. The valve again closes after restoring the pressure balance. This permits air to be drawn in when needed but stops unwelcome odors from entering the house.