We don’t often voluntarily camp in freezing weather, but it’s more because of me than the Airstream. My interest in ice extends to skating, and cubes in my lemonade. Growing up in Vermont, I feel I have experienced enough cold weather to suit me for life. I can see the romantic and novelty factor of frost on the windows once or twice a year. After that, it’s time to move on.

However, if the weather does drop below freezing, the Airstream is not intimidated. I get a lot of queries from people about how we “deal with freezing,” or asking how cold a night we can survive. Really, it’s a non-issue for most Airstreams, because the trailers are reasonably well-insulated against a cold night. There are a few inches of pink fiberglass insulation in the belly pan (under the floor) and the walls and ceiling contain about two inches of insulation as well. All of the essential ductwork and plumbing runs in the insulated space, and of course we have a furnace, which sends some of the heated air to the holding tanks to keep them from freezing.

Last night it was close to freezing here in Cody. We usually set the nighttime temperature at 62, and at that setting the furnace ran several times during the night. Perfectly comfortable. Even at temperatures down into the teens, we won’t have any trouble staying warm inside the Airstream and nothing in the trailer will freeze. Our only precaution would be to disconnect the outside water line, so it doesn’t freeze solid.

A windy night makes it much harder to keep the trailer warm. RV’s are not air-tight, and between air leaks and cooling from the aluminum skin, it’s much harder to keep warm on a windy 30-degree night than on a still 20-degree night.

The real challenge occurs when we are camped without an electrical connection, because the furnace is a big hog of 12v electric power. This is going to be an issue in Yellowstone, since only one campground in all of Yellowstone offers RV hookups and we’re not going to that one.

The furnace chews up about 7 DC amps when it runs, mostly to power a blower. Our battery bank is about 300 DC amp-hours, but we regard only half of that as “useful” power since we are trying to be gentle on the batteries (for long life). In a very cold night, the furnace can cycle on and off every few minutes, consuming 25-40 DC amp-hours by breakfast. Add to that our normal daily power usage and we might drain our batteries by 80-100 amp-hours per day. That means, without careful conservation, we can use up our useful battery capacity in two days.

Keep in mind also that we have four batteries, whereas most newer trailers have two (smaller trailers have just one). Others in this situation will wake up to find their batteries completely flat. They’ll also find they need to replace their batteries every year or two.

Of course, our two solar panels help us out. This time of year, with full sun, we can probably generate 40-50 DC amp-hours per day, which makes up half of our projected use. This means we can boondock in Yellowstone for four nights without draining the batteries below the safe threshold.

However, I’ve booked five nights in Yellowstone, and it will be freezing every night. That means we’ll have to conserve power. We do that by using light and laptops minimally, and setting the thermostat lower than usual at night. I think we’ll be able to keep our daily power budget under 60 amps per day. That’s going to be important, because if we blow the budget we’ll be reduced to borrowing the Gildart’s generator to make it through the last couple of cold nights. That would probably appear in Bert’s blog, and I can’t have that!

Speaking of which, there will probably be no blog entries from Wednesday night through Monday night, unless we happen to get lucky and park near someone who has a satellite Internet dish. The only place I can get online in Yellowstone is at Old Faithful, and I doubt I will be toting my laptop there. I’ll write daily entries while we are in the park and post them all when we exit the park in Montana on Monday night.