I have a bathroom and walk-in closet that is more exposed to the elements because it's on top of my garage. It would be hard to route addtional ducts to it from the existing unit, and I guess the existing heat/ac unit in the attic is max'ed out anyway. I would like to put a supplemental unit in a little cubbyhole of an attic space that's adjacent to said bathroom and closet. I do not want to add another compressor outside. What kind of self-contained heat/ac unit can be intstalled in an attic space, and how much electrical power would it require? Can you suggest a specific model name to look at on the internet?