Curently have a 18-20 year old furnace . Replace heatpump with new Carrier 3-1/2 ton (bigger than what was there), 15 Seer last year. I "thank God" got the maintenance contract on both the furnance and Heatpump. The service people have been to my house 7 plus times for NO HEAT calls since Christmas Day! Everything from door swtich, control panel, ignitor, etc. etc.
I have Propane GAS backup (when temperature drops below 40 degreees).
My house is a little over 2,500 sq. feet, 275 yards from the Chesapeake Bay (on sand of course) no basement, crawl space with all pipe underneath the house.
The current furnace is 100,000 BTU and I am replacing it with the Carrier Infinity Gas furnace. Which should I get 100,000 or 80,000 BTU? The salesman told me either one would work.