Load calc gives sensible halfway between Carrier 25HPA (with respective ECM Handler) 3Ton and 3 1/2Ton spec'd values. Question? Which will give lowest total heating cost? (HSPF=8.5, Degree days=4500, Design Temp=10F, Heat load=40MBH, Ballance point 4-5 degrees lower with 3 1/2 Ton, Resistance element=10Kw).