Official Test Results: Five Ways to Heat a Tent

[MattJ]

Thanks - that sounds like a good back up plan. The company that makes the kit does recommend using the ducting to protect the thermoplastic hose, however.

If the 60mm ducting rattles around too much in the 3” thermoplastic hose, then I plan to find some 1/4” pipe insulation. I’m thinking that might be a good idea anyway since it would be better than an air layer between the ducting and the hose. I measured the opening in my Propex case - it is 3” exactly so the hose should just fit. I’m so disappointed to have hands full of bandaids (again) instead of finally being done with this!

 

[MANUCHAO]

I don't see me car-camping in temps lower than 15/10ºF, so I'm going to order either the 3" or 2" thermo-plastic tubing and adapting it to my set up... luckily the company (Rubber-Cal) is local to me and i could pick up this stuff the same day...

 

[Mgyver1]

Just curious, has anyone given any thought to the Zodi tent heater? Seems to work on the same principles as the Propex with the actual heater being outside the tent.

http://zodi.com/tent-heaters

 

[Lumpy70]

Propane gets pretty sluggish below -20C and I believe the temp where it stops flowing is -28 Celsius (~-18F)

 

[MattJ]

Propane gets pretty sluggish below -20C and I believe the temp where it stops flowing is -28 Celsius (~-18F)

You can see in the very first post on this thread that I actually tried using a propane tank heater blanket for just such a situation! But it drained my 68Ah battery in about 8 hours. I decided that using my battery to heat propane to heat a tent was just a bit too ridiculous. But fun to try . . .

 

[aaen]

Yup propane freezes/goes back to liquid form in my experience around -25degrees celsius or at least start to cause the pressures to drop and the stove/heater/etc to not work properly.

Another option that I know everyone is against is to put the tank inside the car to warm it up, not while you are driving. Then you can take it out and bury it in snow or wrap it in a blanket. It will keep the temps for quite awhile as it acts like an insulator, or just stick the tank in annex your heating. You won't have to worry about the gas rising into the tent due to the density as it will stay in the annex if there is a leak.

that being said be careful, I have had to do some dodgy things over the years at work to get equipment running in lower temperatures.

 

[MattJ]

Well, the long nightmare is over. I now finally have a long and fully insulated hose that I can use to cycle warm air back through the Propex heater. The photos below show how I did it: 60mm reflective thermal ducting (shipped from the UK) wrapped in reflective pipe insulation inside 3" thermoplastic tubing. And of course, it wasn't as easy as it should have been. I must have got the oldest roll of pipe insulation in the entire warehouse. It had glued itself together, so my wife had to hold the ducting while I tried to unroll the insulation onto it. 30 minutes later I had hands covered with sticky adhesive and cuts from the foil . . . and a badly frayed marriage. But at least I finally got it done!

 

[MattJ]

And here's the photo from earlier in this thread to show the reason I wanted a longer, insulated hose. My plan is to cycle air through both the tent and annex. I learned the hard way that the Propex system works MUCH better when the heater is cycling warmer air from the tent rather than sucking in the cold winter air. The hose I am using in this photo was not insulated sufficiently, so it was heating the forest instead of my tent.

 

[Nd4SpdSe]

Well, Nd4SpdSe said it best:

I'm flattered for the quote. And you could of just stolen/linked the direct image, doesn't bother me

That's why it is frustrating that the kit only comes with a single 5-foot hose. I had to buy parts from the U.K. to replicate the hose that comes with the kit after several failed attempts to make one with local products. That could be a whole separate thread if anyone is interested!

I've been getting my stuff from Heatso.com in the UK as well. Not too bad in shipping to Canada surprisingly for a good price and fairly quick!

After the same complaint from everyone that has one, having to create the return hose thing

I've been running my Webasto without the return for the moment. I want to test the limit of it's heating capacity with just heating the outside air. That'll be the next step. So far it's been great down to 0*C.

While I continue to wait for my Propex tubing parts . . . I realized I forgot to mention another do-it-yourself (or go-find-the-parts-yourself) part of the Propex kit:

The thermostat control is shipped with no back on it, since it is made to be mounted to the interior wall of a vehicle. The raw electronics and wires are exposed and subject to risk of damage. So I had to purchase some plastic, cut it to fit and fabricate an assembly with two long screws, washers and insert nuts. I'm actually pretty proud of how it worked out. No sharp edges, and it almost looks OEM. I guess I could paint the screws and insert nuts black, but I figure it looks good enough as is.

https://r5hrtg-dm2305.files.1drv.co...3sQYri_w?width=4032&height=3024&cropmode=none

https://sjhktg-dm2305.files.1drv.co...gAV6LHIw?width=3024&height=4032&cropmode=none

Looks great!

I look back at some of my original photos where I had the warm air traveling 15 feet through a hose from the Propex unit to my tent and it is almost silly! All I was doing was heating up the ambient air outside my tent as the heat radiated away from the hose.

I'm surprised you went that far and long. Mine pumps in through the center fold flap.

Just curious, has anyone given any thought to the Zodi tent heater? Seems to work on the same principles as the Propex with the actual heater being outside the tent.

http://zodi.com/tent-heaters

That Zodi tent heater has been discontinued for many years now. Problem was it was still burning if you're 12v battery source died, causing fires.

Well, the long nightmare is over. I now finally have a long and fully insulated hose that I can use to cycle warm air back through the Propex heater. The photos below show how I did it: 60mm reflective thermal ducting (shipped from the UK) wrapped in reflective pipe insulation inside 3" thermoplastic tubing. And of course, it wasn't as easy as it should have been. I must have got the oldest roll of pipe insulation in the entire warehouse. It had glued itself together, so my wife had to hold the ducting while I tried to unroll the insulation onto it. 30 minutes later I had hands covered with sticky adhesive and cuts from the foil . . . and a badly frayed marriage. But at least I finally got it done!

I'll be following you and keeping this in mind when I get to that point on mine. I'll be needing to do something very similar.

Regardless, thank you and well done for all this testing!

 

[jacobconroy]

Awesome. Thanks for posting your end results. I'll try something like this in the spring as well.

 

[wanderer-rrorc]

why not use 3in insulated home ducting? it packs up like a slinky and would be perfect for discharge air after the first few feet of metal line..and all of the return air...

plus its cheap...just tape up the ends and use spring clamps.

https://www.efireplacestore.com/sbi...wLeZjJWNN-vfGH_RTaQh8kyiE_HDUlnhoC2PQQAvD_BwE

 

[MattJ]

In the spirit of sharing hard-earned knowledge, which is a big part of what this forum is about:

I am a bit embarrassed to admit that last night I discovered a quick and painless way to insert 10 feet of 60mm ducting into 10 feet of 2.5" thermoplastic tubing. The trick is to slice the ducting with a box cutter down the ENTIRE LENGTH, then coil it a centimeter or two inside itself to reduce the circumference just a bit. I sprayed a some WD-40 on the exterior plastic shell of the ducting to lube it a bit, but that wasn't really necessary. I discovered this trick by disassembling the 5 feet of tubing/ducting that was shipped with my Propex kit. I bought the kit from a distributor here in the US that got the parts from the UK, so the distributor couldn't answer my questions about how to build more insulated tubing. My previous posts in this thread provide detail on the misery that followed. Now it seems obvious to me that a simple side-cut is the best way to shrink the circumference of the ducting! Oh well . . .

Anyway, I just wanted to update this thread with that piece of advice. Hoping to try out the new Propex circulation system soon. Will post more pictures when I do.

 

[trailscape]

That Zodi tent heater has been discontinued for many years now. Problem was it was still burning if you're 12v battery source died, causing fires.

I tried building a version of one from a Zodi shower at one point. It's still sitting on the shelf, but it did seem to work. To solve the battery issue, I was considering a selenoid valve on the propane tank tied to the duct fan.

This was a test of the heat exchanger. I put steel duct flanges on each end and made a better mount.


Disassembled Zodi hot tap

 

[jmlarson]

All:

I was directed to this page from the SmittyBilt Scout trailer thread, as I am getting ready to do some winter camping with my young kids. We will be in Zion, expecting night-time temperatures in the 30's. How fortuitous that after having no winter to speak of, we had about a week with temperatures in the high 30's low 40's this last week to test out various setups.

We tried the Little Buddy heater as mentioned - too warm even on low setting....
We took an electric blanket, slept on top of it inside a sleeping bag...toasty warm on the bottom, cold on the top
We took an electric blanket, slept on top of it inside a sleeping bag, with a 750w heater set to about 60...that was about perfect
We used an electric mattress pad on the bottom, sleeping bag, electric blanket on the top, comforter on top of electric blanket....too toasty, even with the electric blanket on 3 of 20 and the mattress pad on 5 of 10. Turned the electric blanket off in the middle of the night

The power consumption numbers (for the entire night) seem to be somewhat contrary to what I have read previously on this post, so here is the data taken from our 'kill-a-watt' meter we reset each night before bed.

Electric blanket only - 0.4kwh
Electric blanket and electric heater - 6.5kwh
Electric mattress pad and partial night with electric blanket - 0.5kwh

0.5kw@ 120 v = 4.2AH. At 12v = 42 AH. Very doable with a 105Ah battery....

as to the comments about the electric blankets not feeling warm to the touch, they generally do not, but based on our experience my suggestion would be you give them another opportunity. They really are power misers, and do good job keeping you warm...

The true test will be in about 2 weeks!

 

[Bluedog225]

Great post. One more option. I just got a titanium wood stove. See e.g titanium goat. Nice dry heat for the annex. Worth checking out.