Have a AC with gas furnace forced air system that is working fine but getting near its life expectancy. When it goes I am contemplating switching to a CCHP (Boise ID) with a air handler (and electric backup if necessary). Short of doing a Manual J is there any reason to not use the BTU's and tons of current system to size the CCHP? Is there some need/formula to size the CCHP differently than current system? Example: will a 1.5 ton CCHP perform much like a 1.5 ton AC unit or will a CCHP rated the same BTU's as a gas furnace perform the same?
Not going with mini splits as duct system is sealed, well insulated, and quiet even with older tech. Reason to switch from gas heating is that I have solar panel array that is producing more than I currently consume so cost of energy will be competitive. Thanks.