A plenum in heating, ventilation, and air conditioning (HVAC) systems is
a box that connects to the HVAC system
. It has a critical function and that is to bring in, distribute, and remove air. … A return plenum takes in that used air and, using the ductwork, sends it back to the core HVAC system.
What is the purpose of a plenum?
Plenum boxes are usually situated on either side of the fan or heat exchanger and have the important function of
bringing in, distributing, and removing air
. They are the air’s first stop after being heated or cooled and its last stop before going back into your AC, heat pump, or furnace.
What is the difference between a plenum and a duct?
A plenum is an air distribution box designed for forced-air systems on residential homes and commercial businesses. It is part of the ductwork, but
far different than an air duct
as these important boxes handle air as it enters the ducts and helps to recirculate it within a system.
What does plenum mean in HVAC?
In building construction Plenum is
a separate space provided for air circulation for heating, ventilation, and air-conditioning
. It is commonly found in the space between the structural ceiling and a drop-down ceiling or under a raised floor.
What is a plenum and where would I find one in HVAC?
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.
Is a plenum necessary?
If there is no sheet metal duct;
just the open ceiling or wall space
, then you are required by law to use Plenum Rated cable. … The lack of wall or ceiling return air grates is usually a sure sign that you require Plenum Rated Cable. Computer Rooms typically use a raised flooring system for the server racks.
What size plenum do I need?
I prefer a plenum
at least 2 feet long and 4 feet is better
. (The branch ducts are sized to the air needed to the various rooms. This sizing is more critical for getting enough air where you need it. Figure an air velocity of 500 to 600 feet per minute in the branches.)
How much does a plenum cost?
Generally, a return air plenum will cost
approximately $50 to $60 per unit
. The other costs to consider are those for the labor and materials needed to install the return air plenum. The installation takes an average of about five hours with the sum of labor costs between $290 and $370.
How does plenum ventilation work?
A plenum in heating, ventilation, and air conditioning (HVAC) systems is a box that connects to the HVAC system. … A supply plenum works
by taking in the new cool or warm air from the heater or air conditioning system
and, in turn, distribute it throughout the building using the HVAC’s ductwork.
Why plenum box is used?
Plenum boxes are used
for supply and exhaust of air through diffusers and grilles
. The plenum box ensures a continuous flow to the diffuser, and plenum boxes equipped with dampers create the possibility of adjusting the diffuser on an individual level.
What’s the difference between plenum and non-plenum?
Plenum-rated cable has been manufactured to withstand higher temperatures in the event of a fire and does not cause the same level of smoke or toxicity when burning. Non-plenum does not have these characteristics, and as a result costs much less (
usually half as much
).
What is plenum rating?
Plenum rated cable has
a special insulation that has low smoke and low flame characteristics
. Plenum cable is mandated to be installed in any “air handling” space. … This qualifies this ceiling as a plenum ceiling, and all the cables that go through that ceiling must be plenum rated.
What makes a space plenum?
Simply stated, the NEC defines a plenum area as, “
a compartment or chamber to which one or more air ducts are connected and that forms part of the air distribution system
.” It also references, “the space over a hung ceiling used for environmental air-handling purposes,” and, “areas beneath raised floors for information …
Where are HVAC dampers?
Typically in most homes, your HVAC dampers are located in
the main supply trunks
. The supply trunks are the parts of the ductwork that are blowing warm air or cold air depending on the season.
Should the plenum be insulated?
Supply and return air ducts and plenums shall be insulated with a minimum of
R-6 insulation
where located in unconditioned spaces and where located outside the building with a minimum of R-8 insulation in Climate Zones 1 through 4 and a minimum of R-12 insulation in Climate Zones 5 through 8.
What is an exhaust plenum?
The Exhaust Plenum is used on GE radial Gas Turbines. The plenum essentially acts as
an “enclosure” or Exhaust duct at the back of the Gas Turbine frame
. This assembly aids in directing flow, left, right, or up to the downstream Exhaust system.
