I have a Cape Cod with 1000 ft2 on the first floor and an apartment in the attic. In a few years I may get rid of the apartment and build up a second story + attic. Both the first floor and the attic currently have window AC units. The heat is hot water radiators and the boiler is on gas.
Does it make sense to install high-velocity AC in the crawl space for the first floor and later, when I build up the second floor, add another AC system in the new attic to cool it?
Or is that going to be too expensive?
I'm thinking that a dual zone system would be nice anyway. Are two AC systems twice as expensive than a single dual-zone one? Or what is the ratio? Also, what are the prices of such systems?