I have an unheated cottage during the winter months in Upper Michigan with all the water drained to prevent freezing. Whenever, when I use the place during the winter I haul in my water. I would like to keep the cottage unheated but still leave my water system intact in my crawl space with out having to drain the entire system back to the submersible pump. The unheated living area above the crawl space would not have any water in the kitchen pipes, bathroom, etc. My crawl space is sectioned off where the pipes are located and measures 10'W x 20' L x 3' H. The crawl space walls are insulated with 3" of styrofoam and the floor above has 6' of fiberglass batts. Could I leave this area unheated and would the temperature that naturally comes from the ground be enough to keep the pipes from freezing or would I need a heat source and if so what would be the minimum and type of heat source that would be needed? Has anyone had experience in doing this?