I know a lot goes into furnace sizing. That said, I'm replacing a 17yr old,
100,000 btu Bryant. It's probably 70% - 75% efficient. My home is two floors, about 2,400 sqft. I live in Cincinnati, OH and we can get some pretty cold stretches. I'm putting in a Rheem 90% + modulating and have two reputable quotes. On says a 90,000 btu will do just fine. The other says a 90,000 is 'maybe just enough' and suggests going to the next step, a 105,000btu. Any suggestions?