Central Ohio, mid 70's house, a little over 2700 sf.
Had 4 contractors come out. One sized based on the size of old system, 2 did short form manual j's based on the plans, only one actual measured the windows (but estimated insulation and air leakage).
Want to go with 2 stage variable furnace and single stage ac.
Everyone suggested 80k 95% furnace (most complete manual J recommended 100k at first based on a 78k heat loss, but once I mentioned he agreed). The two short forms are at 3 ton AC while the other is at 3.5 ton.
I am most comfortable at the moment with the one who actually measured windows, his knowledge, and price (works with utilities to make sure I get all discounts, others didn't even mention), but am afraid once I make some improvements on the house I would only need 3 ton. He assures that I wouldn't be able to get down to 3, but how sure can he be estimating insulation and air leakage? My only concern is that he was quick to oversize furnace.
Without seeing my house, what do you think about recommendations for my climate and my concerns? Am I overthinking the half ton? Do I need to keep getting quotes until I am 100% certain with one?
Thanks for the help!!