I have an opportunity to purchase a brand new Heil 100k 92% 2 stage natural gas furnace for an unbeatable price.
The house is in Buffalo, NY, 40 yrs old, 2 story, 1800sq ft plus a finished basement, new LOe 3 windows, 8-9 ft ceilings, marginal insulation in walls and attic.
I know that a single stage 100k furnace would be too much heat. My thought is that this could work with the furnace operating at 60% for the majority of the time. I am looking for thoughts and ideas as I am trying to make this work. The plus is that I can install this for far less than the smaller 80k furnace, what I am looking for are the possible minuses that I might encounter.

Thanks.