The floor downstairs is still 64.8 and holding steady.
I took the AC downstairs this morning (it's 66 right now) and ran it on the floor for about 20 minutes, set to 65 degrees.
Since it was just pumping heat from the the front to the back, there wasn't any heating or cooling, just some dehumidifying.
Since the coldest air down there is right on the floor, it was a good test to make sure the compressor would come on and stay on.
My test plan is to mount the AC in the wall of the little Landry room.
I'll make a strong platform five feet off the floor, and cut the AC
hole-in-the-wall as large as needed.
The basement intake air 5 feet up will be warmer.. And the cold output air
will sink to the floor.
I'll post again when I've done some more work.