Before you think I'm crazy, listen to my scenario. I have a 1200 sq ft downstairs and there is a 600 sq ft addition above the carport (only upstairs area). I have one 3 ton unit for the entire house and upstairs is 20+ degrees hotter in the summer. I have to replace my downstairs unit because I don't have a heat pump and I'm heating my house on heating strips resulting in $500+ power bills in the winter. Someone suggested possibly taking the unit I am replacing and having it moved to cool the upstairs during the summer since it still works fine. I know it is important to properly size the unit for the area it is cooling because of moisture issues. He mentioned that it would probably work if you were to only use it during the summer and not drop it too low - no lower than 75, 76. He also mentioned a humidistat.

After having 5 technicians out, the concensus is that the ideal solution is to add a separate unit upstairs. I can't afford to replace my downstairs and install a new unit upstairs but I could probably afford this solution if it would work. Thoughts? Or is this a terrible idea?

I live in Savannah, Ga by the way.