I'm building a new house outside Chicago, and I'm considering having the builder install a heatpump (recommended to me by a trusted person). Most of the contractors in my area either don't suggest using this here, or don't believe its a good idea period.

The house is about 2700 SqFt on two floors and has been calculated out to require 99K BTU heating load, and 48K BTU for cooling. (R15 walls, r38 attic, Low-E glass everywhere, 2000 SqFt on English basement unfinished)

My idea is to install a Trane XL16i heatpump at 4 tons, paired with a Trane XV90 5 ton furnace. In theory, this will allow for heating scalability from 48K BTU through 112K BTU at three stage levels.

It seems to me that since the house is built so tight, that a heatpump should suffice during the milder months of march - june, and september - mid december saving natural gas usage for a significant portion of the year.

The operational intention is to lock the heatpump out at about 38 - 43F outside, and then use gas exclusively below this point. My t-stat of choice at this moment is the Honeywell Vision Pro + humidity supporting three stage heating.

My concerns are:

How do you control 4 potential heat stages to use only three??

What indoor coil would be used with this configuration??

Is using a heatpump in northern Illinois a good idea??

Do any of you have other brand suggestions?? (IE..Carrier, Lennox, American Standard, Other)

Any other comments??

Thanks Everyone.