Last year we had 2 straight weeks below 0 in Dec.  In Jan/Feb we have consistent weeks on end that don’t rise above freezing!  I don’t know where you guys live in TN but I am sure you know better than I do.  The problem I have is the hour long drive (interstate 65-70mph, WINDCHILL) to get to my location.  The tanks won’t freeze but the lines might and the water heater is exposed.