Bit of a long question so bear with me. We are just about to break ground on a in-law suite 1300 sq ft one floor spray foam insulation through out. The HVAC contractor has quoted a 2 ton heat pump. The heat pump in the main house is a 3.5 ton about 2years old York. My sister has a 5 ton York about 5 years old that she has just replaced the compressor in, and is having it removed because she is switching to gas. Do you get where I am going here? Would it pay to have the 3.5 ton moved to the in law suite, buy the 5 ton from my sister and put that in the main house which is currently 2500 sq ft soon to have the attic finished which will add approx 800 sq ft.