Cold second level

[joerunner89]

I have a newer home in MN. The second floor is about 4-5 degrees colder in the winter than the main level. The cold air returns are near the ceiling? Is this drawing all the heat from the second floor, or is there another problem?

[deejoe]

High wall returns may be great when in the cooling mode, but imo, are better at the floor level when in the heating mode.
If these existing upper returns are now located on the interior (uninsulated) walls, you may be able to cut
in a lower "leaf dampered grille" that is in the SAME stud space. Then, provided this stud space is clear of girts, or other blockage to the high one,you will then be able to alter the return air with the seasons (low dampered grille open for the heating season, closed during the cooling season.)this is known as a "high/Low' return.
IF, the stud space is blocked by a girt,etc, you still will be better off by just installing a damperless grille near the floor level.

[docholiday]

I would look at two things. 1st, is there a problem with the isulation in the attic allowing you to loose so much heat upstairs? And then I would consider having the system balanced to the design. I dont think the high wall returns are the problem. Many times wall stack is used to get from the basement to the floor between 1st and second floors. If they ran those up the outside walls, they may be losing quite a bit in velocity and temperature.