-22 degrees for the low this Wednesday

Good advice, a trouble lamp with 100 watt bulb works well, as do the magnetic oil pan heaters. A one hundred watt bulb will keep an underground water utility tank vault or pressure control station from freezing. Wow, I'm glad I don't fight those battles anymore when the weather gets like this!
https://shop.advanceautoparts.com/p/zerostart-magnetic-heater-200w-120v-6-15cm-power-cord-3400017/7710020-P?navigationPath=L1*14919|L2*14995|L3*15534|L4*-49997221