You need to keep on looking, as it appears that no one did a proper heat calc. The fact that 2 guys came up with the same size furnace could be dumb luck. The fact that there are IDENTICAL homes is of no consequence. Turning the orientation (to the sun) 90 degrees could change the heat gain/loss characteristics.

You also need to have your duct system evaluated, as it could be presently undersized. Going to a larger system could cause problems, the least of which is noise.

Also, for any meaningful information, post complete model numbers (furnace, condenser, indoor coil).

V

wmas

most upper end furnaces 95% + efficient are sized in 20K increments beginning at 60 KBTU.

you want to be sized correctly for both heatring and AC. no guessing allowed. I would not want to be undersized by a 1/2 ton for AC in July/August heat.

if this was my decision and you planned to be in home for many years, i would want a 95%+ eff furnace and a rated 15 SEER AC.

I would be lookin g at Trane/AmStd, Carrier/Bryant, Rheem/Rudd.

IMO

Stay away from the weasel. Dealer competency is the biggest factor in your ultimate satisfaction, performance, and longevity.

To add some more info, all were asked regarding Trane XV95 and XR15

The first bid quoted.
XV95 TUH2B080
XR15 2 ton 4TTR5024

Second bid proposed
XV95 TUH2B080A9V3
And XR15 2.5 ton 4TTR5030
This bid also specified evaporate coil 4TXCB031

The third bid quoted
XV95 and, I think misunderstood me and quoted XL15i 3 ton with no further specification.

I can always tweak the specifications, I guess and boost one unit up or
down, or clarify with the one company that I am interested in XR15 and not XL. But what is what is concerning me is the issue of the size differences. The first and second salesmen did come in and asked some specifics. They looked at windows and doors and measured off the entire interior of all rooms. I believe they noted the fireplace and skylights, as well. One inputted it all in a software program and came up with the 2.0 - 2.5. The second guy took notes and went back to his office. A few hours
later he sent me a very clear email with all info easy to read etc. For all I know, he may have done computer calculations back at the office

The third guy just came in, looked at the existing equipment and duct work, the chimney, as the others did also, and sat down and wrote the proposal. To be honest, unlike the others, I don't even recall him measuring the furnace, closet or existing sheet metal.

Lastly, briefly, what constitutes a proper load test and how best for me to get that. It seems that even the more established and certified Trane dealers around here may not be providing them.

Thanks for all the input.

A quick way of noting whether a load test was done is if they give you exact numbers on cooling load - like 28,400 btus. They could be making it up of course but it is a clue. You could just ask them, but they could lie.

I didn't trust my HVAC guy when building but he did send me the numbers which included measurements when I asked.

I don't know but I might walk the neighborhood, find an identical house with identical orientation. It is a bit aggressive but it might be helpful to ask the homeowners how their system is. If they had 2 tons and no problems in the summer, then you'd have some comfort. But likely they are oversized and then you can't really tell.

West facing windows are the big issue with cooling load. Next is infiltration and that is a big unknown. I would generally think a 20 year old house in a cold climate would be reasonably sealed but it really depends.

The load test requires window sizes and wall lengths like the one contractor did.