We're in the process of designing a new house, although that seems to be on hold due to no offer on our present house. General plan is to build a tight house with foam and good windows. I plan on having Manual J, D and S run by an independent firm to have as a second opinion to contractor.
The Greenspeed/Evolution Extreme is an attractive option. I have a cousin that is a 50 plus year Carrier dealer in Houston (similar weather, but we have longer seasons) and he is very big on the 2 speed Infinity HP and not so much on the Greenspeed, but I have the feeling he leans toward the tried and true for his customers.
Is there a record of reliability being established on the Greenspeed? I've read comments on how expensive electronic boards, etc can or would be.
Also, if I go with a Greenspeed I think that would restrict the contractors I could have bid on the job if the installation of these does require additional training. A friend that is a home builder (may or may not do mine) currently uses a independent HVAC company, if that is the right word for someone that isn't a factory authorized Big Four dealer. Very competitive price wise and he can install Carrier or Bryant. I can't judge duct sizing, but I have seen some of his installations and the quality of his ductwork installation is outstanding. I wonder if I will have to scratch a company such as his off the list if I choose the latest generation equipment?
The new house will probably be similar to our present one and that is 2500 sq ft first floor, 1100 sq ft second floor with a 400 sq ft bonus room over the garage. From reading the forum, I imagine the Manual J will allow two 2 ton units, one up and one down and I would probably lean to a mini-split for the over garage bonus room. I will also be very open to a ventilating dehumidifier and something like an Aprilaire motorized damper for fresh air exchange.