"That means he could twist his words after executed the contract with me?" If you were buying a new Honda Accord, would you accept that no specific model number was put on the sales contract (ex. LX, EX, EX-L, 4 or 6 cylinder)? It is the same thing in HVAC equipment. You are paying for a specific size and model for each piece equipment. Perhaps you trust the HVAC contractor to do the right thing, but more often than not it does not happen. If you have low humidity (less than 30%) then you may want to invest in a humidifier, otherwise you don't need.

The proper way to determine the size of the furnaces and AC condensers is to do a heating and cooling load calculation. For new construction I strongly recommend you have the HVAC contractor do the calculation and review it with you. I also recommend both furnaces be installed in the basement. Installing a condensing furnace in an attic in a cold climate like the Chicago suburbs is risky. It can be done, in my opinion your are far better off installing it in the basement and running the duct work to the second floor. This is how it is done in my house and it works fine. American Standard and Trane are the same equipment built by the same company. They are considered two of the better brands as long as you stay away from the low end models which builders tend to use. As a general rule general contractors know very little when it comes to HVAC. They will sub the job to the lowest bidder. It is an area where builders try to get away with spending a little as possible. Stay on top of this and ask a lot of questions.

canadasteve what is something good worth? usually it's whatever the market will bear, in other words whatever people will pay. when you phrase the question like that, probably not. Get another quote. Bryant, sister company of Carrier, has the exact same model. Check their price. there is nothing to say you can't make an offer. all they can do is say yey or ney. IMO

I've had a couple (I think reputable) HVAC contractors out to quote the replacement. So far, none of them have measured any rooms or windows, asked about or verified existing insulation, or counted registers. They did look at the overall size of the house and percentage of basement vs. crawl space. With the most recent one, I specifically mentioned that one room is particularly warm (we have only been in the house during cooling season, so I'm not sure how it performs in heating season). He suggested insulating the ducts (they are currently un-insulated through a crawl space) but did not suggest verifying CFM to that room. Surprise, surprise, the quotes have been coming back the same size as the existing unit (4 ton) or 1/2 ton smaller. Should I be expecting a more thorough analysis before receiving a recommendation and quote? I asked the last guy about this and he said they "guaranteed" the correct size. If we needed bigger or smaller after install they would change it out at no charge. I'd rather know it was sized correctly and just install the correct thing the first time. Any advice would be appreciated. Thanks in advance!