Correction: I spoke with the builder and all walls are indeed insulated. Only the ceiling is not, which actually works out because it would make wiring work for the installation of lights a little easier from the attic, I can insulate it myself after the wiring is done with minimal work. The garage door is also the insulated type so it looks like this thing is going to be easier than I had envisaged [8D]

The only question is, do I get a mini-split system as LNEWQBAN had proposed, or do I simply tie into the existing HVAC system in the house which is easily done from the attic... I like the latter better for obvious reasons, but if I do that I wouldn't install a return as it would be safety hazard (someone at some point could leave a running car in the garage). Not sure how well a vent without a return would work in a (fairly well) sealed room. We could argue that a garage is not very well sealed, which I agree, but to have positive pressure in the garage with air escaping, there would have to be negative pressure in the house to make up the lost air flow. Not sure how that would work with a home HVAC system, if anyone with this kind of background could chime in with some ideas that would be great.

********nut - thanks, I'll check it out when I get settled.