There are a few places where heat tape is the best option. But I still don't like counting on electricity to keep things from freezing. You would be surprised how much heat a big cistern or storage tank full of water can produce. It takes a long time to freeze a big tank of water like that. You can utilize that heat by cutting a big hole in the wall where the pipe comes through. A good insulated box over the pipe on the outside is needed. Then a big 12" hole instead of just a 1" or 1 1/4" hole through the wall for the pipe, will let heat from the well house keep the pipe from freezing. You could still use heat tape, but this way it may not be needed. There are lots of different kinds of heat tapes. The only ones I have used are the cheap, short ones found at the box stores.