I'm in the process of getting quotes for central air for my 80 year old house. It is a 2 story, 1485 sq ft brick single house, with ample space in both attic and basement. Two estimates came in for a 2 zone system and two estimates are for 1 unit system. It will a ductless, conventional air installation. I'm wondering if 2 systems is overkill for such a small house. Maybe the labor is less involved (down from the attic and up from the basement) so it is easier to install and that's why it is being recommended? Or would 2 systems really make sense? Excuse my ignorance, this is very overwhelming and any help is very much appreciated.