What size Gas Furnace and AC do I need?

farinc55

I have 2 floors, one of which is a basement. Each floor is about 900 sq. feet, so 1800 total. I've read that when calculating the BTU and Tonage requirement that you only use 1/2 of the basement square footage, thus reducing the total square footage to 1350 if true. Can someone tell me what size BTU gas furnace (80%) and A/C tonnage (14 seer) I'd need for my situation? Thank you.

pecmsg

The only correct way of knowing is a ACCA Manual "J" Heat load / Loss calculation! All those calculations you read about do not take into account the local conditions, house construction infiltration etc etc.

I do advise for A/C get heat pumps for the mild seasons and 2 stories 2 systems.

EBEBRATT-Ed

As @pecmsg said rules of thumb are not the correct way to size equipment. Every building and every location change the heat and ac load. You need a proper heat loss and heat gain calculation.

If I was forced to take a rough guess I would say 60,000 btu on heat and 2 tons of cooling but location and building construction will dictate.

Hot_water_fan

Manual J. If heat loss is low enough, a heat pump only is probably a better idea. But furnace + heat pump works too.