There is an old mission church with three foot thick stone walls that is cool year round near Tucson. We do have solar, but no backup battery (came with the house). The canal runs half a mile near our house. I can take the heat, and children are pretty acclimated. If we could even go two hours north to Flagstaff, the elevation brings the temperature down considerably.
Yes, I left out the word ‘battery’ in front of bank.
How about Show Low as a refuge from heat? Doesn’t seem like a particularly ‘showy’ or fancy place but that may be just what you need. I would like to visit in summer.