Plenum
Definition and meaning of Plenum in real estate.
A plenum is a main chamber or duct in a heating, ventilation, and air conditioning (HVAC) system that distributes or collects air. It acts as a central hub connecting the furnace or air handler to the individual supply and return ducts throughout a home.
In more detail
Every central HVAC system typically has two plenums, including a supply plenum that distributes conditioned air and a return plenum that collects stale air. The supply plenum connects directly to the heating or cooling source and distributes air into the supply ducts. The return plenum draws air from the house and channels it through filters back into the HVAC unit for reprocessing. Proper sealing and insulation of these chambers are critical to preventing energy loss and maintaining air quality.
Key facts
| Category | Property Types & Construction |
|---|---|
| Applies to | Forced-air heating and cooling systems |
| Watch out for | Air leaks and improper insulation |
| Typical location | Directly attached to the furnace or air handler |
A home inspector notes that the seal between the furnace and the sheet metal supply plenum is failing, which is causing conditioned air to leak into the crawl space.
Frequently asked questions
What is the difference between a supply plenum and a return plenum?
A supply plenum distributes newly heated or cooled air into the home's ductwork, while a return plenum pulls air from the rooms back into the furnace for filtering and temperature adjustment.
Why does a plenum need to be insulated?
Insulating the plenum prevents condensation from forming on its metal exterior and reduces energy loss as air is heated or cooled.