38.8 °F presently ( I just measured it)
OAT = 8°F
Predicted -5°F tonight.... calculating........
-13 degree delta would equal... well lets say somewhat below 32°F!!!
Hmm, need to get up at several times and run some water to keep lines from going solid.
I could solve that by having a reason to flush the commode several times tonight.
OK, THAT I can solve!