I don't have a copy of the basement floor plan. However, it did come with the house plan and it was so well done, that we made very few changes. The only rooms that do not have windows are the play room and the bathrooms--which is fine by me. The basement windows are large and to the south. We also have tall ceilings down there and it does not seem like a basement at all. The house is 3500 sq ft, so not as big as you may have thought--although certainly big enough. We finished 3000 sq ft in the basement. We don't really need the upstairs great room either, but surprisingly we do use it. I have my baby grand in there and it has NO television. I do love my home. I wanted a home that was elegant but not pretentious, like so many new homes in my area. It took us about a year to build and we had a terrific building experience with the best builder I could have hired. We did time and materials, which I know is frowned on here--but for us it worked out well.

I guess I'm confused -- it would be an understatement to say HVAC is not a strong area for me. I don't know what you guys are visualizing, but here the heat pump and blower typically go outside and you just need clearance to run ducting, vents, chase, and an air return on each level. Since the house is sealed very tight, there's a fresh air system, too, but I have no idea what that looks like. I do have an attic, so placing the unit within conditioned space is preferred if it can be worked out. Heat pumps can either be package units or split systems. With a package unit, everything is contained in one box (package) which usually sits on a outdoors pad directly against a wall. The ductwork runs through the wall connecting the system to the house. Package units are sometimes also installed on roofs. Package units are cheaper than split systems, but always lose a little bit of conditioned air to the outside world. Package units are common on mobile homes and not that unusual on site built houses in mild climates. The most common arragement is the split system. With the split system, the compressor sits on a pad outside, while the air handler is installed inside the house, ideally in conditioned space. Refrigerant flows between the two units in copper piping. All duct work is connected to the air handler, which is where the indoor blower and other components are located. Air handlers come in vertical and horizontal configurations. Horizontals are usually found in attics, while verticals go in the basement or HVAC closet. Speaking of attics, you don't want your air handler in the attic, unless you have no other choice. The HVAC guys hate working up there for good reason. It's cramped and often very hot, so it's not a fun place to install or work on something, especially a broken down or new unit in mid-summer. You will find some of the worst HVAC work in attics. Air handlers generate condensation, which needs to be drained off. A malfunction in the condensate removal system, usually a pump, can result in water dripping in the attic, which can cause structural damage if not caught in time. While attic air handler installations normally have an overflow float switch for a safety mechanism, these can fail. In my opinion, an air handler should only be installed where 1... it can't cause damage if the condensate drain malfunctions, and 2... the homeowner can easilly inspect it every now and then. Air handlers installed in attics usually don't get inspected until something goes wrong. If your attic is not conditioned space, you absolutely do not want the air handler up there. None of them are perfectly sealed, so you will lose conditioned air to the attic. The air handler in our new house during installation. I assume your fresh air system will be an energy recovery ventilators, or ERV. ERVs make sense in the humid South. Here's what the unit installed in our new build looks like. The ERV mid installation. Two more ducts will be connected to the left side. A lot of home plans make absolutley no provision for the HVAC, so the systems end up wherever the installers can fit them. Usually that means the homeowner loses some sort of closet space to ducting and returns, while the air handler gets stuffed in the attic. In my opinion, plans for homes built in AC or heat pump country should include dedicated space for the HVAC installation, including the air handler, supply and return ducting, and air returns. Too often this is not the case. If you locate the air handler in the basement, don't forget to spec a floor drain for the condensate.

Update: Last night, shut off valve fixed. I cut 2 small holes (enough to get my head and an arm in) in the ceiling in the basement and a smaller one in the wall. The first hole in the ceiling was in the floor space where the 2 recess lights are that the water was pouring out of. Sheet rock was completely dry, couldn't feel any dampness at all. Second hole in the ceiling was directly below the toilet and it was slightly damp but not bad at all. Have a fan up there now blowing. Smaller hole in wall toward the of the ceiling, no dampness and insulation dry. I honestly don't get it. Could it be that it was because it was such a short period of time that the water ran and it had a place to escape that it doesn't seem wet? Maybe it's because the other end of each of these spaces goes into my unfinished storage room which also gave the water another place to go? I have fans in there as well blowing up into the spaces now. It appears that I've caught a break (unless I'm missing something?)

Maybe try BM Moonshine, or SW Comfort Gray. I know you said grey hasn't worked in the past, but maybe it's just a matter of finding the right one. With basement lighting, in a perennially overcast area, everything will look different in your room. I would take the time to try loads of swatches. Like, I would probably grab 15-20 paint chips, and look at them at home. From there narrow it down to 5-10 to get samples of, and paint large swatches. It's a pain, but it's worth it.