Hi all,
I found out this summer, much to my horror, that the wheel wells in my class C had no insulation over them what so ever. This amount to about six square feet of metal acting as a heat sink.
The passengers side was no problem to upgrade. I covered the entire area (about seven square feet) with a 3/8 inch closed cell foam pad and then doubled over a sleeping bag to get rid of the problem.
On the driver's side this was not possible. The "designers" had wires, propane supply and fresh water plumbing laying directly onto the metal. No wonder there were "freeze" issues! I was able to "work" a 1/8 inch piece of foam between the various pipes and the metal of the wheel well.
I've done my first "winter testing". With outdoor temperatures at -10 C and the interior of the RV at 8 C, the fan I used to replace the cold air return under the kitchen cabinet kept the temperature at above 4 C.
As I would normally run the inside of the RV at 18 or 20 C, I think I have the fresh water freeze problem licked.