Well, the outdoor unit is sized at "two tons," but it's the easy part to change. The indoor unit is an "air handler" or something like that, with an electric furnace, and they'd have to build a sheet metal thing to fit it into the space available, apparently, because now they're wider than they were when the house was built. And then there's the existing ductwork, which needs to be repaired (in one case) and cleaned - there are either eight or nine ducts. (My house is 1152 square feet.) I had been told he would send us the bid last night, but we didn't get it yet.