Traveling in the Cold

Claybe wrote:
Sorry forgot to mention that I have a Majestic 23 Class C motor home. The water tank is under the bed and I will be running cab heat the whole trip. I had already thought of using the RV antifreeze in grey and black tanks. Just wasn't sure if I would be able to use the fresh water tanks. Sounds like I shouldn't risk it until the freeze clear zone (basically until I reach my destination). Wouldn't rock salt and antifreeze accomplish the same thing?

The fresh water tank won't be a problem when you're traveling, as you'll have the interior heated enough to be at least somewhat comfortable. "under the bed" is part of the interior, as it's above the (nominally insulated) floor and inside the (nominally insulated) walls.

If the grey and black tanks and drain valves are enclosed in a compartment and the plumbing doesn't run exposed underneath, you should have no troubles whatsoever with things freezing so long as you use the furnace and don't leave hoses hooked up. Often with enclosed holding tanks there's a duct from the furnace into the wet bay to help keep it above freezing; that, along with running the pipes within the heated envelope of the RV, are what constitute a basic four-season capable RV.

Rock salt in the holding tanks is a perfectly reasonable antifreeze, and perhaps more effective than diluted RV antifreeze. You don't really want either rock salt or RV antifreeze in your fresh water tank if you can help it, for obvious reasons.

I've camped in below freezing temperatures in my class C and it's been pretty much uneventful. The furnace does use a relatively large amount of battery power (and propane), and the single pane windows and general lack of sealing/insulation can make it seem (and indeed be) somewhat drafty. If temperatures are very cold, well below zero say, things could be rather more complicated.