Block upper level air return in winter?

I have a 1.5 story house with a 20x20x20' great room that has a giant air return on the side of the room below the thermostat and 2 supplies near the windows on the opposite side of the room.

in the corner is the hallway for the 2nd level which overlooks this room and up high there is another return vent, along with one in each bedroom on that level. I think much of the warm air from the great room gets sucked away by the vent on the upper level which is visible from seating position.

Would it make sense to block this during the winter and reopen in summer when cooling?

I have a ceiling fan in the room but it doesn't help to divert much back down.

 

Am I reading this correctly - some or all of these returns are near the ceiling and not the floor?

 

The main level return is at the floor, all others in the house are up top. 2nd floor upstairs is upper and overlooks great room. I blocked it no noticed difference yet.

 

Have to be careful blocking returns. Unfortunately, I don't have a good suggestion for you other than adding returns lower in the rooms.

 

upper return is going to pull that warm air in and dump it back out on the floor at your windows.

 

well the 2nd level is 500sqft and tehre's 2 beds/bath and hallway there, the 2 bedrooms each have a return also... i've left the hallway one blocked and it seems to help comfort at least in the 20x20x20 room open to that hallway