I was considering the possibility of combining two units into one. The upstairs is on it's own system as is the lower level. I have been toying with the idea of getting a single unit that is smaller than the combined load required for both and setting back the stat in the upstairs during the day and the downstairs at night.
I stumbled across a flaw in my initial design as the supply air would be dumping in the downstairs during the heat of the day but the return upstairs would still be drawing in air that is 10* hotter than the downstairs air.
Can dampers be installed on returns so that they open only during a call to that zone? I guess I wouldn't be able to set the upflow AH on a plenum box as a always closed damper would need to be ducted.
Total Gain- 42,859
Total Gain- 40,747