All my tanks are located in one bay and no plumbing in any of the other bays. My webasto buffer tank is also in the same bay so if i am in danger of falling below freezing there is more than enough heat dissapating from the webasto system to keep the tank bay warm. The hydronic system operates on diesel or electric, i have heat pumps on the roof which have worked well into the teens, and I also have propane heaters. No danger of getting cold for me.
Back when I was young and foolish and parked my bus in NH for the winter at my folks house, all I used in my water bays was a 60W light bulb which I left on 24/7 and my tanks never froze. This in most cases is sufficient. Of course if you are away for a while, or in a much colder climate, it may be better to use two bulbs just in case one blows out. Also, you should use a rough service bulb as they are much more rugged and are less like to blow out it they get knocked with something.
Ho ho, Gary, you must have been in Southern New Hampshire to get away with that. I was up North past the Franconia Notch where it got down to 40 below, and we kept loaders running all the time so that we could use them. After a few weeks of below zero, it took a long time for things to recover. I miss the firewood stoves in the garages, it sure made it cozy (within a few feet of the stove).
You are a strange duck Don lol 8)I have saw those type ducks
hum.... One reason for owning a fuel sucking rolling back of scrap metal is to drive it to where you don't have to ask this question. Our mission is if it's hot head south, if it's cold head north until you feel just right. LOL
LOL and this guy lives in AZ,but we do wear jackets when it is 70 degrees