Thanks for the info guys. I got an email back from the builder and they said that I can talk with the superintendent when I do a walk through soon. They will show me the load calcs then. 3.5 may be good with all the insulation, brick, low-e windows, etc that they put in....we'll see. If the load calc comes out too close, then I will make sure they put in a bigger unit.
Also, on e the unit is fully installed, it's going to cost you a lot more to pull it out and put another in. Also, a 5TR unit will have a lot more CFM than the one you have, requiring them to change the trunks and cost you even more. If I were you, I wouldn't wait for a walkthru...
