It doesn t matter how much you run the air conditioning system during the summer that second floor will always stay much hotter than the first.
How to install a cold air return on second floor.
The air flows across the ceiling in the hallway towards a larger cold air return that does extend to the basement furnace.
The ducts in this 1800 sq foot home were all installed in the 1970 s.
Running a metal cold air return duct between studs requires knowledge of both hvac systems and the components involved in framing.
Install the square return air duct perpendicular to the joists.
In an air conditioning climate the return duct goes near the ceiling to draw off the hot air and cool it down.
So i guess back then cold air return on the 2nd floor wasn t as important.
You do this and i guarantee you that the second floor is going to be much more comfortable year round.
In a heating climate the return duct goes near the floor to draw off the cold air and heat it up.
Divide the house into two zones one for each floor.
At that point you could cut in a large central ceiling return in the hallway of the second floor as centrally located as possible.
You want to run it so it covers up all the holes you cut in the panning.
Build a return air box above the opening tall enough to accommodate the properly sized flex return air duct going over to your closet r a drop having built the same r a box in the attic over the closet drop.
For 1800 sq foot home including finished basement they put a luxaire 80000 btu 92 high efficiency single stage furnace.
If the supply ducts are high or in the ceiling then the return air ducts or grills should be low on.
You might also want to try adding a ceiling fan in critical rooms like a second floor bedroom.
The problem comes when you use both heating and air conditioning.
Add a small return vent duct to each room on the second floor.
If you are in the far north or in the southern us the answer is simple.
The return air vent openings need to be on the opposite side of the room so the conditioned air is pulled across the room.
You did bring up an interesting point.
For 1 the furnace fan running all day with the a c on might solve some milder heat trap problems for your second floor.
Air circulation in homes which are older and or in poorly designed newer ones equipped with a central forced air system might be compromised because they do not have an air return port installed on the second floor.
Return air duct is connected together using s slips and drive cleats.
Cut holes in the top of the return air duct to match the holes in the panning.
If the supply ducts are in the floor then the return air should be located up high.
