bcar the general conscensus is that you get better control and ccomfort with two systems over one system that uses zoning controls for a large living space with just one system. you need to take that into consideration, your overall satisfaction with existing system, and the ductwork modifications required to go to one system with zoning controls. you may be required to give up some living space as well with one system. then there is the qualifying process of finding a capable HVAC dealer to do the job. look for experience and references that you can call and perhaps visit. as far as remote access and iPhone usgae, this is rapidly changing everyday and you need to rely on dealer for advice on this subject. I know Trane and Carrier have remote access capability. I do think that Carrier along with sister company Bryant offer the best integrated system for residential zoning on the market. And certainly I would be very careful in selecting a third party control/stat just to get remote iPhone access/capability. IMO

ionized - thanks for the comment and I will definitely look into adding a humidifier later on vs at the beginning. I moved from a house in the North Hills that was your typical 1950's Pittsburgh Cape Cod and in the winter we had a big problem with static which I would like to dry to avoid in my new home. I realize I might be off the mark for my reason on humidity control but in general, I just want to do this system right because I have that option. to all - can anybody give me a range that I should be paying for a new high efficiency system (as spec'd above) from either Trane, Carrier, Amana/Goodman, or York for my size house? Quotes as mentioned before are on top of each other so thats what makes me comfortable with them but it would be nice to hear from someone on here as a sounding board. Thanks to all the previous comments and suggestions.

Thanks for the comments tigerdunes. We've been over this quite a bit already. The pricing is average for the North East....labor rates tend to be quite high and the $600 rebate makes the price of the furnaces excellent. I obviously have two stage thermostats and the sizes of the furnaces were decided after heat loss calculations. I live in an older home in a cold climate and my calculations were within 10% of my contractor's. The calculation for my two floor unit came in at 75kBTUs. The contractor initially wanted to install a 100kBTU unit, but I talked him down to 80kBTU. The furnace for the renters below me is a bit large, but it was the smallest two stage available from American Standard. I thought about installing a 92% efficient 40kBTU single stage furnace with selectable motor speed, but as the 60kBTU two stage with variable speed motor was the same price after the rebate I went with that one.so that both furnaces essentially the same and to get the variable speed blower. I imagine having the second stage will also be nice on very cold mornings.

I am a little skeptical of this calculation. The summer temperature is a little too high, and the winter is not low enough in my opinion. Some of the numbers are strange. The heat gain from people is about the same as the walls. Do you have many windows facing the south? You have 1.5 tons of heat gain just from the windows. There is a big loss for the fireplace. I would have thought that would be covered in the infiltration number. "Existing unit cooled and heated satisfactory (when it worked). Of note, both Family room and Foyer have 20 foot ceilings." If this statement is true, then there is no need to increase the size of the furnace or AC. The Trane dealer sizing seems more realistic. Get a third quote if you want more data points.