As long as there s an unobstructed path e g no door that can be closed the upstairs doesn t need a dedicated return.
Attic furnace no return plenum.
Ceiling space as a return air plenum.
As noted by one previous poster all materials in the attic must be plenum rated.
Not to mention that the air handler itself is in its own plenum.
Static pressure but it is usually 0 5 wci.
The rating plate will state the max.
Anyhow the return box and the other box that has the ducts coming out of it are made of sheet metal.
If there is no return duct the concept is that the attic space becomes a return air plenum and this is not uncommon in commercial plenums.
My mother has had me going up into her attic to seal the leaky ducts and parts of the plenum air handler that join up to the furnace and coil units.
How can and attic be held to the same standard as a plenum when its used for storage and water heaters and such.
No return air plenum.
The sealed attic is great with return and supply duct inside of the thermal envelope of the building.
Tesp is typically measured using a manometer and a dwyer 303 static pressure tip inserted into the return plenum just before the filter and in the supply hopefully before the coil then add the two numbers disregarding signs.
Inspectors can learn how air leakage from ductwork may cause home energy loss increase utility bills lower comfort levels and make the hvac system less efficient.
The return is on top and the supply is on the bottom.
Building cavities used as return air plenums is one of the leading causes of duct leakage in homes today.
Cabling is not rated for plenum use.
An attic is a space not a structural component the space cannot support anything but air.
The return air plenum was a room with doors and banks of filters.
If the space is conditioned it no longer is an attic and needs to be called conditioned space wiring within an area used as a plenum has to be in conduit.
Everything would need to be plenum rated including the low voltage cabling.
A 14 trunk too small emerges from the foundation wall in the basement in a roughly 2 2 notch at the top of the foundation wall.
I used to work in house at a 40 story high rise.
Reality returns should be ducted with a small supply and return connected to the attic space.
No radios or storage.
Otherwise this is a code violation.
I think a cmp cable cost twice a non rated cable so my guess is all your communication fire alarm and misc.
The major drawback is what material can go in your plenum.
You ll also need to provide a return path from a basement air handler or main level return to the second floor.
