First - love the degree symbol! Used to do the whole "alt-" thing on my Windows XP machine - not sure how to create it on my Win 8.1 version... Gotta agree with Don - my exterior shower is just a breach in the insulated wall - plumbing isn't even sealed to it (on the list for warmer weather...). Using the propane furnace doesn't mean plumbing gets any more heat than using electric (or some other source) in the coach. Not all furnaces are ducted, or at least ducted towards plumbing. Just need to keep cabinets open to allow warm air to reach the pipes. I've found a little fan helps in that regard. ST