Heating, ventilation and cooling (HVAC) systems consist of many different components, including plenum boxes.
Located in the duct work – right before the air handler or furnace – they play an important role in warming and cooling your home’s interior. Depending on the type, a plenum box may be connected to the supply outlet or return ducts.
For more information on how plenum boxes work, keep reading.
What Is a Plenum Box?
A plenum box is an HVAC component consisting of an enclosed box that’s connected to the ducts.
You can usually find them around your HVAC system’s air handler or furnace, which of course is also where the filter is located. The air filter sits between two plenum boxes. To change the air filter, you’ll need to pull it out from between the plenum boxes.
Plenum boxes are used to distribute heated or cooled air throughout your home’s interior.
After producing heated or cooled air, the HVAC system must move that air through the ductwork. Plenum boxes take in this air so that it can be pumped into the ductwork and, therefore, distributed throughout your home’s interior.
Return vs Supply Plenum Boxes
There are two primary types of plenum boxes used in HVAC systems: return and supply. While both are located around the air handler or furnace, they work in different ways.
The supply plenum box connects to the supply outlet. It receives heated or cooled air from the furnace or air conditioning system, after which it pushes this air into your home’s ducts.
The return plenum, on the other hand, connects to the return ducts. Most homes have both supply and return vents. The return vents suck in air, which is then carried to the return plenum.
The return plenum helps to recirculate air while also removing particulate matter from it. Prior to entering the return plenum, the air must pass through the filter where it’s cleaned. The cleaned air will then go into the return plenum where it’s distributed into the ducts.
In Conclusion
Plenum boxes are moderately large enclosures in an HVAC system that contain heated or cooled air.
In a typical residential HVAC system, there’s a single supply plenum box and a single return plenum box. They are used to distribute the heated or cooled air throughout the ducts so that it can reach all the rooms in your home.
If you are experiencing a problem with your air conditioning or heating call us at 512-336-1431 to schedule an appointment. We’ll be glad to come out and take a look at the issue.
1431-183 A/C & Heating proudly serves Round Rock, Georgetown, Cedar Park, Pflugerville, Leander, Liberty Hill, and North Austin.
I have a one-car garage that has been converted into a room in a house that I am renting. The room is always cold in winter and hot in summer. There is a supply duct that is about 3 to 4 inches wide but no return. How can I get the system balanced so that all rooms have the same temperature all over the house? Oh, the outside wall of the converted garage is insulated.
Mike,
I just noticed that behind my return air filter is a large space about 3 feet deep and 2 feet deep. This space has trash and dust from when the house was built in early 2020. I always thought this space should be much smaller and cleaner since it negates the need for a filter (air is being sucked into a dirty space). Your thoughts Please?
Thanks!
I have a one-car garage that has been converted into a room in a house that I am renting. The room is always cold in winter and hot in summer. There is a supply duct that is about 3 to 4 inches wide but no return. How can I get the system balanced so that all rooms have the same temperature all over the house? Oh, the outside wall of the converted garage is insulated.
Additional info, this is a 1600 sq feet home and the outside wall of the garage is insulated. The a/c unit was just updated from a two-ton to a three-ton unit.
How many square foot is the converted garage?
Additional info, this is a 1600 sq feet home and the outside wall of the garage is insulated. The a/c unit was just updated from a two-ton to a three-ton unit.
How many square foot is the converted garage?
The initial investment for an HVAC system may be higher than the typical gas furnace, but the long-term, energy-saving benefits are noticeable each month. The size of the HVAC system helps in saving especially when it has fresh air.
The initial investment for an HVAC system may be higher than the typical gas furnace, but the long-term, energy-saving benefits are noticeable each month. The size of the HVAC system helps in saving especially when it has fresh air.