With the help of the great info I've gotten from this site, I have my bids down to two. Both are Lennex units, the high-efficiency variable speed furnace (G61V), with slightly different AC units (one using R22). Otherwise, most of the differences are minor: 1 year warranty on labor vs 5 year, whether I need a condensate pump or can use the floor drain (previous owner put in a non-code shower stall using the floor drain as the shower floor! No exhaust vent, either.)
My big problem is that the furnace sizing is different between the two bids, and they do not seem that close! I think the difference is sizing is due to our finished basement. It gets quite chilly, especially in the winter. I mentioned this to both reps, and one is going to put in two cold air returns, the other says it won't do any good.
The rep who will put in the returns is going with a 45,000 BTU unit, the other rep is sizing a 70,000 BTU unit!
Now to me, that seems like a pretty big variation. I've read here that oversizing a high efficieny furnace is bad and awful, so I'm concerned.
Here are the stats: I live in a 1960 ranch (aka, the shoebox) in MN. There's over 16 inches of blown in insulation in the attic. There is insulation in the walls,but heaven knows how much. Half of the basement is finished and the other half (split the long way) is laundry, mechanicals, and a half-bath with the "shower".
In the finished half, there are two vents in the basement ceiling, and one lone return. The other (unfinished) side has only two vents, no returns. Other than the basement, the house is pretty comfortable, the bedroom walls gets cold in the dead of winter, but the room itself is comfortable.
I checked the estimates that didn't make the cut, the size is either not calculated (sizing to my existing unit, or the "I've seen a thousand of these homes, and they always take...") or fall right in between the two bids. Granted, I had a total of 6 bids, so there isn't a lot to average. I'm going to try the HVAC calc, but I'm concerned that I can't address the comfort variables in the program, and I think that is the source of my problem.
So, experts, what do you think? Is the difference between 45,000 and 70,000 not as much of a difference as it seems to me? Or is one of these guys not doing his homework correctly? I want to be comfortable downstairs, but don't want to bake upstairs or oversize my furnace, either.
Any advice you can give will certainly help me to make the right choice!