Duct Plenums

A plenum is an air-distribution box attached directly to the supply outlet of the HVAC equipment that heats or cools the air to make the house comfortable. The ductwork that distributes the heated or cooled air to individual rooms of the house connects to the plenum. The HVAC equipment has a blower that forces heated or cooled air into the supply plenum and from the plenum into the rooms through the supply duct system. Air-cleaning filters may be located in the supply plenum.