Our central AC is totally unbalanced. The top floor (where the bedrooms are) cools off quickly but downstairs, especially the great room with it's vaulted ceiling are still warm. I hate to waste money (and chill DD who naps and goes to bed way before us) freezing out the top floor just to be comfortable downstairs.

How crazy would it be to make these zones separate? I don't want to bother if it's so expensive it wouldn't even be cost effective. If it makes any difference, our vents are in the ceiling and we have baseboard heat (which IS zoned separately).