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Discussion Starter #1
Hi,
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:
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.

Water System:
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.


Grey Water:
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.


Furnace:
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.


Propane use:
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.

Battery Use:
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.

Gary
 

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I just glanced over most of what you typed, so I may have missed something.
I caught the part where you said you insulated the water supply tank.
My initial thought is, if it is inside the van, you basically insulated it from being warmed from the interior van heat. So, if I read that correctly, insulating the tank inside the van, hurt more than helped.
 

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I was wondering that too....unless what you are insulating is heated.....all you are doing is insulating it from the ambient van air.
 

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Discussion Starter #5
I just glanced over most of what you typed, so I may have missed something.
I caught the part where you said you insulated the water supply tank.
My initial thought is, if it is inside the van, you basically insulated it from being warmed from the interior van heat. So, if I read that correctly, insulating the tank inside the van, hurt more than helped.
Hi,
I did not explain that very well.

The problem water line runs across the van through the floor just under the floor plywood -- The floor is insulated with 1 inch Polyiso, and I placed the pipe with as much insulation under it as I could. There is no insulation between the top of the pipe and the floor plywood, but probably only about half an inch of insulation below the pipe -- apparently not enough for -10F :)

The picture shows the white pipe going into the space between 2 Polyiso panels with as much Great Stuff under the pipe as I could get in.



Maybe there is another way to run the pipe across the van and get more insulation between the pipe and the van floor sheet metal?

Gary
 

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I'm still in the design stage myself having to run a water line from one side to another is something I'm trying to avoid,but may have to embrace once the design is done. We will likely be fair weather travelers, but, if I were faced with your scenario, I might consider a low flow 12v pump somewhere in the system, to periodically circulate the water.
Maybe run a bypass at the sink pump and another line back to the tank, so you can circulate and move the standing water out of the lines. Not sure how you have it set up or if you have a water heating system. Maybe a mixing valve in combo with a recirculation pump?
 

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Sounds like a lot of work, but I assume you are married to the design/layout at this point (?).
Frozen water lines are a headache and a half.
 

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One nice feature of the elevated bed, or even an elevated platform or step at the back of the van layout, it that is allows for water and electric lines to cross to the other side as needed, above the finished floor. That advantage is what keeps me looking at floor plans that don't run a full aisle down the middle of the van front to back. But then again, I haven't started the build out, so I still have time to mess something else up ;-)
 

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After my cabinets were complete, I needed to run the power to the Webasto rheostat across the open floor. A groove on the underside of 3/4” ply took care of it. Enlarge the scale for the diameter of water pipe and it should be a simple matter.
 

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Those kind of temps are not for me anymore but I respect those of you pushing the boundaries of camping this way. My water usage is low so my foreseeable plans are to keep my van free of plumbing and rely on water jugs (active one balanced on the edge of a table), wash basin, etc. Since it's just me (wife no longer interested in camping or travel) and I lost most of my sense of smell in a rock climbing accident when 16 ;-) it works.
 

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Discussion Starter #12
After my cabinets were complete, I needed to run the power to the Webasto rheostat across the open floor. A groove on the underside of 3/4” ply took care of it. Enlarge the scale for the diameter of water pipe and it should be a simple matter.
Hi,
My floor paneling is only 1/4 inch thick, but maybe I could rout a groove in a door threshold for the pipe -- that would allow a full inch of insulation below the pipe.

But, it would add a bit of a tripping hazard.

Gary
 

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Thanks for the post Gary

always informative.

All my lines are on the warm side with the exception of my drain thru the floor to an exterior hose bib. I can isolate that line with a miniball valve on the warm side. I have drained the van now as we are starting to get to freezing temps now (Even the warm side is only warm when in use 😳)

Other than the cold, I bet Banff was beautiful this time of year.
 

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I have insulation around my fresh water tank which is totally on the warm side (inside) of my van

I used the insulation to “pack“,the tank between plywood panels to prevent movement - not for R value as it does not work like that.
 

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I uses about .75 gallons of propane with my Truma in Bryce last week. (26 deg F.) to keep at 65 at night (12 hours) and 45 during the day on the road).

Winnie built my van with all PEX. Don't use PVC.

 

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Discussion Starter #16
Thanks for the post Gary

always informative.

All my lines are on the warm side with the exception of my drain thru the floor to an exterior hose bib. I can isolate that line with a miniball valve on the warm side. I have drained the van now as we are starting to get to freezing temps now (Even the warm side is only warm when in use 😳)

Other than the cold, I bet Banff was beautiful this time of year.
Hi,
Banff was great as usual -- and really quiet this time of year...



We feel fortunate to live only one long day away (and with Glacier Park on the way) :)

Gary
 

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Hi,
Banff was great as usual -- and really quiet this time of year...



We feel fortunate to live only one long day away (and with Glacier Park on the way) :)

Gary
So Beautiful

The roads dont look too bad. I do not have much snow experience in our PM (just a little in North Calif I-5)
 

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.........cut..... 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). ......cut.....
Thank you Gary, great information. Awesome trip by the way.

I have a question regarding furnace: do you trust capacity/rating is accurate?

Your 10,000 BTU/hr estimate is about 3,000 Watts of heat, which kept you about 70 F above ambient. That matches well with our camping at about half that (60-25 F) with 1,500 Watt electric heater, but I have an uninsulated window van.

I’m wondering whether the furnace doesn’t put out that much heat (10,000 BTU/hr), or if insulation isn’t as effective as we think?

Also, why did you only use 1-inch of spray insulation? Was it cost, space, weight, fear of warping wall, or what?

Thanks again.
 

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I think there are a lot of things that are a matter of taste/preference and can be overdone or just be good enough, according to personal priorities.
In my opinion, if efficiency in heating, cooling, maintaining temp, saving electricity and fuel source is something that is a priority, then insulating properly and thoroughly is worth the effort. I know that even a little insulation is better than nothing, but in my opinion, it's one of those things that is worth doing well, or don't bother.
If you're not concerned with saving every drop of fuel and amp hour spent on climate control, then it's not critical.
 
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