I have begun the design process for a new house, which will be about 18,000 total heated and cooled square feet -- main house (first and second story) are approximately 11,000 S.F., attached garage 1,000 S.F., finished basement 3,000 S.F., and finished attic (third story) 3,000 S.F.

The house is in New Jersey. I desire radiant in-floor heat, and central A/C with all supplies on the ceiling. There will be many coffered ceilings, so I'm thinking there will need to be a lot of those "strip-style" diffusers that blend in nicely with the mouldings.

First question... should I be getting a commercial HVAC contractor in here? I want a top-quality job, nothing that I'm going to have to go back and "revisit" after it's done.

Second question... I'm confused about whether I entertain the idea of one big air-cooled chiller with several air-handlers for the central A/C, rather than have like 10 individual split-systems. However, with a chiller and air-handlers, can you get the same effect as with a two stage compressor and variable speed blower (for excellent humidity control)? Really good humidity control is really important to me.

Third question... with the in-floor radiant, I'd like nearly every room to have its own control, BUT, I don't want to have to go around to 30 thermostats when I want the heat on... is there any type of control system out there where, from one "master" thermostat, I can set all the heating zones to, say, 68, and then use the individual stats in each room as an override? And also see what all the stats are set at from the master, and change them from there?

I know I need to get a really good professional in here to make sure it gets done right, but as the house is still in the planning stages at the moment, I want to make sure I do my homework to make sure I get the right people in here and know what are and aren't good ideas. So I'd really appreciate any feedback. Thanks!