This cant be emphasized enough. Every time i do a nice tight rehab i cant get over how little energy it takes to keep it warm and cool. But then you have those who will open the windows on 95 degree days when the house is 75 inside.Spend some bucks sealing leaks and improving insulation on the house and you may only need 2 mini-splits. Improvements in the house envelope's insulation will payback year-round during the cooling and heating seasons.