Get to Know Your AC System’s Plenum

No doubt a lot of words come to mind when you think of your central AC system, but we’re betting that “plenum” isn’t one of them.

Poor plenums of the world…so frequently overlooked by homeowners but doing so much to keep them nice and cool. So today, we dedicate this blog to the two plenums attached to your system’s air handler and the role they play in the overall scheme of things.

The diagram shows you half of your AC system. Not the outside condensing unit, but the air handler usually found in an attic or some other out-of-the-way indoor spot. As you’ll notice there’s a plenum on either side of it – one for supply and the other for return air. 


Your AC System’s Plenum

Image Courtesy of Building America Solution Center

Supply Plenum

The supply plenum is a box that is connected to your HVAC system’s supply outlet. Your AC system’s blower sends cool or warm air into the supply plenum, which is then distributed throughout your home through your ductwork.

Return Plenum

The return plenum connects the return ducts in your duct network back to your HVAC system. Many return plenums contain filters to remove bacteria and other contaminants from the indoor air that passes through them. The air is then sent back into your HVAC system for another cycle of cooling.

Importance of Proper Plenum Installation

Like any other system component, proper installation is key to operating efficiency and cleaner indoor air. Basically, AC installation is not a job for weekend warriors, but it is a job for the licensed and insured HVAC team at Air Professionals.

For more information or to schedule a free in-home AC analysis and new system proposal, contact us today.

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