Zaz, I have a small 1500 watt electric heater running inside my well hose 24-7 right now. Our last cold snap a week ago caught me off guard because I had a 250 watt heat bulb above my well pump, but the copper line going from the pump to the pressure switch froze,this line was not under the heat lite,so water froze in this small line,thus not allowing the pump to turn on as the water pressure got lower in the pressure tank.
Within 15 minutes time I had a cold water line freeze in a back bathroom because the water was not running constantly. For those who don't experience this sort of cold very often, water needs to be a small stream out of a faucet,,,,not a drip-drip-drip sort of running, it will still freeze if just slowly dripping because it is not moving fast enough. Another thing many don't realize if a line does freeze, open that faucet completely up. Remember if water freezes in a line, It will continue to freeze more and more and expands. If you turn off that faucet completely as the water continues to freeze it has no more room to expand, causing the pipe to crack much faster.It can buy you a lot of time by as soon as you notice water isn't flowing to open that faucet completely up. Hot and cold water both needs to be turned on to the point of a steady-small stream to keep from freezing up when it's 5below,as it's expected here again for the next several nites. Yes I said HOT water too must be in a small running stream because sometimes your faucet is 50-75ft or more from your water heater and by the time it reaches that faucet by just dripping, it will be cold water, not hot as when it first came out of the water heater. I coincidently have a big 175,000 btu kerosene space heater and a 55,000 btu propane heater that I use when a pipe freezes. the sooner it gets thawed, the less chance you will have of a cracked pipe.I don't have much trouble until we get to about 10 degrees or less temp wise but the wind is always a huge factor here.