Now that the issues are corrected for my main level system, I now have a question about my upstairs HVAC system.

I had a Lennox SL280v gas furnace installed last July. This week has been pretty chilly here in Georgia. We have been having comfort issues in our 3 bedrooms upstairs, and they haven't started yet until the temperatures got pretty cool here outside. The thermostat is located in one of the bedrooms which has high ceilings. The other two bedrooms have standard 8 ft ceilings. I have noticed that the temperature in the room with the high ceilings is always a few degrees warmer than the others. For example, during the afternoon that room was 69*F and the other two rooms were both 64*F. The doors were open all day. Plus, the bedroom with high ceilings has curtains over the window and faces the sun the majority of the day. I would assume that could be part of the cause of the unbalanced temperatures. My son has been complaining that his bedroom has been cold in the afternoon right after he gets home from school. My daughter's room is the room with the high ceilings and her room feels nice. The third bedroom is the guestroom, which is hardly used. We had our attic insulation evaluated last summer and the contractor said that the insulation was all fine. The furnace has also been having very short cycles as well (like in the 3-4 minute range).

What could possibly be a good solution to solve the unbalanced temperatures upstairs? We do plan to have a service tech out soon if this problem continues.