In Great article  by Duliskov on backup electrical power, he suggests a propane tank heater/cover to counter low temps that reduce available propane. I noticed it’s a spendy item. Depending on your conditions, you might get by with one of these  and a blanket. Speaking of low temps, just a reminder of how handy thermostatic switches  are as part of a freeze-protection system. My pump house is very well insulated, but I have a 100W bulb on a thermo switch which comes on if needed. Best regards, – D.O.