Thinking of adding return duct to improve air circulation

[JojoToto]

I have a 2 story home. Each floor has its own heat/AC system. My 1st floor cooling is adequate.
However, my second floor A/C is running almost non-stop because not enough cool air circulates to the area of the thermostat. All the upstairs rooms are 3-4 degrees colder than the thermos area with all the doors open. The game area with no obstructing walls is about two degrees colder. The second floor has a single return duct on the opposite side of the house.
It seems that the cool air does not reach the 2nd floor thermostat even though the area is wide open.
Is it a good idea to add a return duct somewhere close to the thermostat to help pulling the cool air to that area?

Thank you in advance for your advices.

[bobRitchie]

Why not move the thermostat?

An open upstairs hall will always be a little warmer.
If you want/ need to cool the hall more you need to add a supply
duct. But you still probably want to move the thermostat into
a room, not in an area open to below.

Just a homeowners opinion.

[DanW13]

If you have to independent systems, one for the upstairs and one for downstairs the downstairs will almost always be cooler than the upstairs even if you only had one system for both as cool air falls and heat rises so it makes sense that your upstairs is a few degrees warmer.

If the stat is centrally located in the upstairs you should be getting a even reading on the stat, you could check this with putting some cheap thermometers in each room to verify. I would if possibly put separate returns in each room to help with air circulation IMO, however it will also help to have at least R-50 Insulation in the attic space, ensure all ceiling penetration are sealed and you have the attic access sealed around the opening to keep the conditioned air from escaping into the attic will help a great deal.

You also might want to check your duct work to make sure it's all sealed, if you have flex duct in the attic make sure it's pulled straight as possible, and the turns/ells are not kinked in anyway to provide maximum airflow to your supply vents. You should also check your return duct and make sure that is sealed so it's not sucking in hot air from the attic back into your return causing the equipment to run more than necessary.

[sktn77a]

With two systems, the upstairs should be at the temperature of the upstairs thermostat and the downstairs should be at the temperature of the downstairs thermostat. You could add an extra return to even airflow out or just move the thermostat somewhere else, whichever works best. I suspect a second return would even out the upstairs airflow more and therefore be the better solution.

[JojoToto]

Thank you for all your advices.

I know that upstairs is always warmer than downstairs. In my case there are always 2 degrees difference. So I set the thermostat downstairs to 77, and upstairs at 79. At this setting, the upstairs bedroom tempratures will reach 74-76 degrees (that is too cold) so I always leave the doors open so the cool air can move out; the game room temperature will be at 77. The thermos area can barely reach 79. That area does not have any return nor supply duct.

I can try moving the thermostat to the game room, but I still have a problem with that warm spot.

How about adding a fan to the game room to help circulating the air? I turned on the fan downstairs but it did not help.

[udarrell]

I'd get a 20" vertically adjustable floor type fan to circulate the air.
Relocating the room stat is yet, also an option.

It also sounds like it could use more Supply & Return.
You need to know how to figure that out so it will work properly & be affordable, BEFORE you begin to make any changes! - Darrell

[Cool_Air]

:confused:
I have a 2 story home. Each floor has its own heat/AC system. My 1st floor cooling is adequate.
However, my second floor A/C is running almost non-stop because not enough cool air circulates to the area of the thermostat. All the upstairs rooms are 3-4 degrees colder than the thermos area with all the doors open. The game area with no obstructing walls is about two degrees colder. The second floor has a single return duct on the opposite side of the house.
It seems that the cool air does not reach the 2nd floor thermostat even though the area is wide open.
Is it a good idea to add a return duct somewhere close to the thermostat to help pulling the cool air to that area?

Thank you in advance for your advices.:cool:the location of the Tstat needs to be located close as possable to the area of the return and I don't think a second return would hurt . Any thing over 2.5 tons calls for two returns. The first thing you should do is have a manual J load cal. done and then manual D for the proper air to reach each room.Believe me it WORKS GREAT.