[jeff5may]

Well, I'm not sure what I'm gonna do yet. I'm torn between a couple different options. Let me explain.

This top portion, if I built it, would be for my son's bedroom in the basement. He's one of those people who has to have it 75 in the winter and 65 in the summer. The bedroom is approx 250 ft^2 and is long and skinny. It is bordered on 2 sides by the uninsulated poured wall, so the top 2-3 feet of those 2 walls floats with the outdoor temperature. This winter, the temp on that portion of the drywall got down into the high 40's as the outdoor temp approached zero. Even with mt dirt cheap heat pump running in the unfinished portion, keeping it in the low 70's, he felt he HAD TO run a toaster-style space heater in his room.

I'm not sure how the space does during the cooling season yet, since we moved into this place in September. If it heats up as much as it cools off, I'll probably need the thing to heat and cool. Not a major problem, it just complicates the part most people don't look inside.

I am also considering making this new machine provide hot water as well. If it does, it would have one heat exchanger for dhw, one for room comfort, and one outdoors. I don't want the room blower to run off house water pressure due to the possibilities of contamination and/or having a massive leak trying to flood the basement. I can pretty well isolate the dhw loop from mayhem, but the room heater mixed with kids will need to be dummy-proofed.

I may end up making two separate units, though. It would sure be a whole lot easier to design. But if I had one unit doing it all, I could heat water and cool the room at the same time. Due to the uninsulated basement issue, I don't want to cool the basement during the winter while heating water.