I don’t know why - But your single air exchange heat pump driving a single head unit in the 9,000-12,000 range seems to be incredibly efficient. Once you go to

I don’t know why - But your single air exchange heat pump driving a single head unit in the 9,000-12,000 range seems to be incredibly efficient. Once you go to a larger unit, and more heads, the efficiency drops. It’s fascinating to even see the huge increase in switchable units - running your 4/5 ton unit at 4 tons is much more efficient. (Usually)