We take our PM out a few time each winter, but usually in the 20’sF — we just got back from a 4 day trip up to Banff and the temps got as low as -17F with two nights at -6F and -8F. The weather was clear and beautiful, but really cold.
Thought I would pass on a couple things we learned …
The overall message to me was that camping a few nights at -10F ish is a big step from camping at 20F, and if you plan to do it routinely, you probably want to do your conversion with really cold temps in mind.
Heat loss at -10F is about twice the heat loss at 25F.
Our van is a 136WB, high roof. Its insulated with urethane spray foam to about 1 inch on walls and ceiling and 1 inch polyiso on floor. We use Reflectex thermal window covers.
The PM itself did fine. It cranked a little slower at -8F, but started right up both cold mornings.
The PM heater worked fine to heat the front of the van — did not have to run it at maximum even with -10F outside.
I put some effort into making our water system handle low temperatures: https://www.buildagreenrv.com/prevent-water-system-freezing/
Basically the fresh water tank is inside the van, and its insulated all around with polyiso, and we have a quick and easy way to drain the plumbing — this allows us to spend time out of the van without heating it to keep the pipes from freezing.
Well, this failed at -10F. Even with the van heated, the pipe that ran across the van from tank to galley in the floor froze up and we were not able to get it to unfreeze for the whole trip. We ended up buying some gallon containers of water and used them.
So, the pipe running through the floor insulation across the van is a weak point for really cold weather. I will probably add a low wattage heater wire along the floor pipe (see link above), but if doing the conversion over, I’d think about trying to get the fresh water tank and galley on the same side of the van with compact plumbing and with a quick and easy way to drain the plumbing.
Also, the temperature in the cabinets that back up the van wall run colder than the van air temperature, so some means to circulate van air through the cabinets with plumbing is a good idea.
Our grey water tank is under the van, and anything that goes into it in cold weather freezes. This seems to work OK for a few days as long as we don’t let the tank freeze when its full of water. But, you can’t drain the grey water tank until you get to temps above freezing, so not a good solution for extended stays in cold weather. Our tank is homemade out of MDO plywood, but in past RV’s we have let plastic tanks freeze with no ill effects — but, not guarantees. We usually put some RV antifreeze down the drain to lower the freezing point a bit.
We mostly drove during the day and used the furnace at night to heat the van to about 60F inside.
The furnace is Suburban 16K BTU propane, and it worked without a hitch.
It was comfortable, but increased body radiation losses to the cold walls and drafts along the cold walls were noticeable.
On the -8F night, the 16K BTU input (12.5K BTU output) furnace ran in a cycle with 8 minutes off and 15 minutes — so, it ran about 65% of the time. For this, the average propane use would be 16K*0.65 = 10.4K BTU per hour (0.11 gal/hr). For a 12 hour night, this makes for 124.8K BTU, or 1.35 gallons, or 5.7 lbs per day. Quite a bit.
We use a 20 lb BBQ propane tank, so about 3 days with a full tank would be about it — even 3 days might be tight with the outfits like Rhino that only fill the tanks to 15 lbs.
If we were to use the van routinely in this kind of weather, I would want better insulation to cut fuel usage down.
One thing to note is that if you insulate to the level that we did, and you want to camp at down to -10F, you will want a furnace with at least 10K BTU/hr OUTPUT (likely about 13K BTU input). If you wanted to go down to -20F, it would want to be about 15K BTU/hr input.
House battery use seemed about normal with about 84% SOC in the morning with 12.3 volts.
Very Cold weather camper van thoughts/ideas:
- Better insulation — maybe 2 inches of polyiso and better thermal shades than the single layer Reflectex type. And, some insulation for thermal bridges at the frames: https://www.buildagreenrv.com/insulating-thermal-bridges-due-metal-frames/
- A higher capacity furnace.
- Water system — tank inside the van and plumbing that is compact and does not run through floor/ceiling.
- Insulate the fresh water tank and have an easy way to drain the plumbing so you can let the van go cold when you want to spend a night out of the van.
- Carry one of those Lithium battery emergency start batteries — we have a 13000 MAH one that works well.
- Have a way to allow use of the house battery to help start the van battery
- Some kind of backup heater would likely be a good idea — maybe just the van heater.
- Good sleeping bags.
- Grey water tank — not sure??
Maybe others who operate in really cold temps have more ideas/solutions?
If you are out in the boondocks in really cold weather, things could get serious fairly quickly if lose heat or mobility, so preparation counts.