Backpackable Wood Stoves: Theory and Ultralight Application

[JP]

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[HkNewman]

Think it would be cozy if tent bound in winter and imagined such a system 15 years ago. Glad to see companies experimenting with it but share the concern about tight quarters and an increased fire hazard for smaller shelters. The large cotton army tents we had in the Korean winters would have the fire resistant material surrounding the pipe start to glow red if the stove was getting too hot (someone would be up as "fire guard"). Wonder if there's been any testing as to when it's time to cool the stove down?

[David Thomas]

Adam,

I concur that body heat can be sufficient to heat a certain volume, and even at -40, my own house is so well-insulated and tight that much of the heat needed comes from bodies, cooking, and showers. I turn off my home heating system above 40F/5C because those heat sources plus solar input is more than enough to maintain 70F/21C indoors.

We do this all the time when backpacking and we do it in something called a "sleeping bag".

If you try to go to a larger volume, you encounter two issues. 1) the added weight and bulk of insulation whether it is down, poly, foam, or the air-gap between layers of fabric and (2) moisture build up in the insulated and well-sealed volume.

How do you get rid of the moisture in a well-sealed shelter? In my house, I have a mechanical ventilation system that runs through a heat exchanger. That's not an option while backpacking.

I could imagine in a setting like Everest Base Camp, a tight and insulated shelter that got warmer (+10C?) than ambient due to the body heat inside. I would equip it with mouth pieces and check valves so exhaled breath was exhausted outside the shelter, possibly running through a heat exchanger to warm the incoming air. There would be moisture from everyone's skin, but at least the biggest moisture source would be addressed. But all of that would be tens of kg as opposed to 1 kg for a wood-burning stove that makes a 1-2 kg tent very comfortable, avoids the moisture build-up, and lets you dry your clothes.

Toddlers and wood stoves are definitely an issue. It was one reason we opted to NOT have a wood stove in our house despite living on 6 forested hectares. I'd recommend Erin's book "Small Feet, Big Land*" if you want inspiration on just how much you CAN do with toddlers. Humans have been using fire for at least 400,000 years and it was only in the last generation that there were safety gates around all wood stoves at all times.

* And, as Erin quipped, Let your family read this book. They may think what you do is crazy, but not compared to what THESE people do.

[David Chenault]

I've run the Big Sib as hard as fuel would allow on ~0F nights, complete with glowing red pipe and flames shooting out the top (http://vimeo.com/84734616), and never did the stove jack or shelter material seem in any danger.

Like I said, this seems like a bad idea, but unless you're foolish is not a big deal.

[Anonymous]

@ Adam K. That would be fine on short trips, but Dave seems to go out on longer trips when he can, and in some truly cold temps or otherwise nasty weather.

Part of the problem with these kind of trips is that moisture accumulates in one's clothes and gear, and at those cold temps it can be hard to get rid of.

A small, light stove set up allows you to really dry things out, which can mean the difference between miserable and comfortable. It's not something you have to run all night, or anything. He still has his primarily bag and jacket insulation adequate for the temps.

For someone like me, who can't get out on longer trips, but does mostly 2 day and occasional 3 day trips and in less extreme conditions (i live in VA vs Dave in the far north), a double layer tent would be a good solution. Hence why i'm going to add an IR reflective liner to a small cuben tent and bring a couple of smaller beeswax candles. Add a little heat during these lovely polar vortexes (keep em coming nature).

@ Jerry. I think the 1 mil polyethelene heet sheet type IR reflective stuff is better and tougher than the ubiquitous mylar space blankets–instead of quick tearing like the mylar, they have some stretch and again are thicker also. As long as i minimize rubbing up against it, and pack the Solomid carefully, should last a while. There are better, more durable materials but they are either rather heavy, or quite expensive.

[Steve M]

" I think the 1 mil polyethelene heet sheet type IR reflective stuff is better and tougher than the ubiquitous mylar space blankets–instead of quick tearing like the mylar" +1

This could be 'attached' to one or 2 panels of a pyramid shelter using small flat magnets. I would expect the area behind the stove would offer the most benefits for reflected heat–assuming it's not too close to the stove.

[Adam Kilpatrick]

The moisture issue is a good point, both short and long term. I didn't really think too much about that.

I'd heard about Erin and Hig's trip, but it didn't dawn on me that they had such young kids with them. I'll try and get it for a read, then I'll try and convince my wife to let us do something "crazy" with our kids too. I have been a bit known for the crazy already, so people kind of expect it :-)

[eg worldtrike.crazyguyonabike.com ]

Another thought that popped in my head when briefly looking at the stoves, is has anyone produced something lightweight to make their heat exchange more efficient? Thermal mass is likely out of the question, but lightweight radiator fins on the chimney etc could really cut down on the amount of fuel required. Even just putting a couple of small bends in it would make a big difference. Could potentially be just collapsible aluminium foil (good heat conductor).

[Gregory Allen]

This has been an idea I have found tempting/interesting for a while. We love getting out in winter and shoulder seasons, and keeping warm while moving is never really an issue. The problem for us has always been getting and staying warm after stopping and at camp. So much of what we have always carried during cooler months has been for comfort/survival when we are not moving. This is enough of an issue that many potential overnight adventures are turned into day hikes. The subzero (F) night/days we have had recently haven't made this any easier. Although a wood stove/shelter setup would not replace a good sleeping bag and appropriate clothing, it seems it could make the long nights and cold mornings much more enjoyable.

After reading this article, and a little web searching, I decided to make a stop by the headquarters of Kifaru, which I had no idea was so close to home. They don't have a traditional brick and mortar store, but online the offer the possibility of dropping by and being able view their gear. My wife and I were met at the door of their offices/warehouse by several very helpful employees. They didn't have one of the stoves assembled, but they were quick to run back to the warehouse, bring one up, and a very knowledgeable team quickly showed us the medium oval Ti stove. It was pretty nice, easy to assemble, and incredibly sturdy for the weight. The staff their answered all our questions and were super nice.

Heck, I've carried beer in my pack that weighs more than that thing. Although not negligible weight, it almost seems like a no-brainer for someone like me who wants to get out more in winter but hates shivering while waiting for water for coffee to boil.

Now I just have to justify $400 of titanium foil and a tent mod!

Greg

PS. I have no personal or financial interest/connection to Kifaru or any company that makes stoves. I had never even seen one live until today.

[James Littlle]

Was so glad to see this article. I have tried cold weather camping but being confined to my sleeping bag was not fun. It made the activity a mental test. With this set up I could have an much more pleasant experience. As far as ultra light I feel it still applies. I go as light as possible until the comfort experience is worse than the wieght discomfort.What good is being ultra light but not having a pleasant experience. I am a twig stove user and love it and so I am definitely going to add this to my setup.

[Alpo Kuusisto]

Just tested a different hmmm… out of the box, approach to tent heating.
http://www.timoanttalainen.com/ -> post of February 9th, 7th pic.
Logic behind was that fire not only gives heat but also forces lots of air circulation. Be it a hot tent or a lean-to with fireplace. Handy if you need to dry stuff but unnecessary draft if you don't. Air intake tube, stove and exhaust pipe would be efficient but heavier solution. This was way easier to make and certainly light. And a window is nice to have anyways.

Now question: How do you think I should make the window? Currently it's made of transparent oven safe foil (is this same stuff as mylar space blankets without aluminium?) but this is way too weak. See the duct tape repair in window.
X-linked polyolefin would be stronger but will it shrink in the heat of the fire? Will it develop a big tear if it gets a small hole from a spark? How about PU-tent window material. A bit on the heavy side at least. Or maybe just thinnest most transparent Cuben?
The material should be somehow tear resistant, transparent enough for IR-rays for not to heat up and transparent enough for visible light so that I can see how the fire is doing. It would be nice if it was so clear I could enjoy the scenery too.

[Kevin @ Seek Outside]

We have done a fair amount of testing on ultra efficient designs, and some with reflective liners etc. In the end, the best insulator in cold environments is snow, but it is not reliable. While you can increase the efficiency of stoves, it is often not worth it from a weight or cost stand point. In areas, where wood is plentiful, it's generally plentiful and burning dead stuff does the forest more good than harm by reducing forest fire fuel. Reflective materials have some merit, but once again do not provide all night heat. What they will do , is get a smaller stove to operate beyond what it would without the reflective materials. They are all trade offs. For me, the trade offs are well worth it once the days are short. Having the lightest kit, does no good if you aren't enjoying yourself. For me, packing light is about being efficient, and keeping your mind and body efficient.

[Dena Kelley]

I find this article to be entirely consistent with UL. It may not apply to some individuals here, but it does apply to others.

I see this type of tent system used frequently by sheep hunters in Alaska. By the very nature of what they are doing they pack as light as they can but often they take a 'Mid and a UL wood stove these days because the gear has gotten light enough to make it feasible. It greatly improves their camp comfort and overall safety.

As David posted, it does also apply to some UL'ers for various reasons. Not everyone is out there without kids, or in good conditions. Kit like this can open up opportunities for people that they wouldn't otherwise have.

[Steven Duby]

I thought this would be a good discussion to add my first BPL post to…

The entire notion that a "backpackable wood stove" is somehow not applicable to "backpacking light" is so unfounded that I almost have to laugh at it. There's a considerable difference between going light, and going minimalist. Obviously if you live in a place where generating heat during minor cold spells is a temporary inconvenience, a wood stove is of little to no use. But, as many of you who've posted here already (especially my fellow Alaskans) understand, the further north you travel, the more you have to deal with the real world….and it's a cold place.

Here in the Interior, most human-powered travelers, whether they are skiing, snowshoeing, fat-biking, pulling a pulk sled or not, if they aren't carrying a wood stove, it's likely only because of the serious weight and bulk…or an abject lack of fuel, as is the case in most places above treeline. With the advent of new stoves that can be conveniently carried in a backpack (as opposed to a pulk which mitigates the weight factor), this allows more people to travel fast & light with the benefit of a warm shelter at night & in the morning.

I'm willing to bet some of you on here have never experienced temperatures much below freezing, let alone sub-zero. If you are an efficient traveler and only experience at worst the low teens or perhaps single digits on a rare occasion, I would argue against using a wood stove because there are methods of maintaining adequate warmth and comfort which preclude it, thus saving you weight even with these UL wood stove options.

If your primary adventure areas are in the northern mid-latitudes (southern boreal forest, i.e. Northern NY, VT, NH, Maine, UP Michigan, Wisconsin, Minnesota, etc.) or high-elevation areas (sub-alpine) around the continental divide that can see temperatures below zero and at the extreme down to -20F, I would argue that a backpackable wood stove will enhance your winter camping experience tremendously, perhaps extending your travel range beyond what you might otherwise consider.

But if you live in the far north (Alaska/Northern Canada) and regularly experience temperatures past -20, -30, and even -40, having a wood stove in these instances is far more than a luxury item. In many cases, it can be a link to life. Can you travel fast & light at -40 without a wood stove? To a point. Check out Josh Spice's blog (http://www.joshspice.com/2012/01/still-cold.html) for more info on that…but take heed to the fact that the fun factor really starts to take a nosedive once you hit -30. That really is the temperature where, when you lose heat, it takes considerably more bodily work to regain that heat (hence the obvious need for more/better insulation, VBLs, etc.). The further the mercury plummets, the harder you have to work. Eventually, you will reach a point where, once the heat is lost, the only way to properly regain it is through an exterior source. There's no way around it…and that's where the ultralight wood stove in your pack saves the day. Knowing how insidious the cold can be, I wouldn't chance much past -40. Weird stuff starts to physically happen at that temperature, the magic point where Fahrenheit and Celsius meet: no form of water can stay in the air, due to it being the freezing point of the molecule on its own, without attachment to another particle; durable plastics become brittle; nylon crunches when bent; even metal begins to weaken. It's a good time to stay in…and if you're out with that UL wood stove, your only priority might be to gather more fuel.

Now…some of you might say, why bother exploring in these temperatures? I say, why not? If there's technology available that makes going faster, lighter and further in extreme cold less stressful and considerably safer, I am all for it. It opens up human-powered winter travel in Alaska's Interior as a more viable option in the months of December, January, and February, although lack of daylight will always be a limiting factor in the enjoyment for many.

—

I forgot to mention my thoughts on the Sibling stove featured in this article. There is one serious problem with a bottomless stove, and that is snow depth. As evidenced, a few inches or perhaps just a foot can be managed sufficiently by shoveling it away…but often when camping on snow, the more efficient preparation is to pack down the snow to create a level surface. In that case, with potentially feet of snow separating your shelter floorspace from the ground, a stove like the Sibling would compromise it's own base by melting the snow beneath it.

[Elliott Wolin]

May have posted this in another thread, but in the 1970's I read about a couple who would head out for a full month in the dead of winter in Maine. They pulled sleds so weight wasn't much of a problem, but they didn't haul as much as you might think.

They wore fine-weave Egyptian cotton outer garments (it was reliably very cold), brought a fairly light canvas tent, a collapsible wood stove, an axe and relatively light sleeping bags. The large stove kept the tent warm all night so they didn't need heavy bags. And they carried less food per day because they didn't burn many calories at night to keep warm. Thus they were able to stay out for a month without any resupply.

[Paul Davis]

All: Interesting and useful article.

All over the circumpolar Arctic 'hot tenting' or 'wall-tenting' has been the norm for long stays out on the land for several generations, though wall tents of stout cotton are hugely heavy, as are trapper's stoves (tent+stove 35kg+ 100lbs+ up!).

Living in the Yukon, 60N 136W, I can say that other than dog mushers and trappers, very few people are actually overnighting out on the land in the winter at all.

Trappers tend to have basic relay cabins to overnight in, utility workers have tracked enclosed heated vehicles like the BV-206, and the mushers don't sleep a lot in a race, except at wall tent checkpoints or cabins.

With climate change, which the Yukon is hugely affected by, even building snow shelters has become problematic in odd weather—in Jan. we had a 70 year record high temperature chinook that melted and compacted 70cm of snow into an ice layer 10cm thick.

You literally cannot shovel such an ice layer into a pile to make a Quinzhee snow shelter.

Under these conditions only a hot tent or a miniature wall tent will work.

I have a Kifaru shoe-box sized stainless steel stove, mated to a 4 season MEC Snowfield tent, which is roughly a 7kg package.

7kg is hard to justify on April (last month of winter) bike camping trips— as is the time to set up + effort to secure 14 points of support, compared to a Bibler I-tent with 7 points of support, is significant.

I have used mylarized bubblewrap 'Radiantex' or 'Reflectex' insulation velcroed to the tent vestibule to reflect stove heat back into the tent, with some success. Snow melting for drinking water and making basic add-hot-water food is also easy.

In the Yukon, one dilemma is that Grizzly bears are also waking up from hibernation earlier with climate change—sometimes as early as mid-February, so can one use the wood stove to actually cook in the tent? In the dead of winter, ok, but in spring??

Hence the add-hot-water meals, even eating them 200m away from the tent, and washing the tent once in town, to reduce the chances of attracting a bear…

I am in the throes of planning a 200km fat bike road ride to Skagway, through the mountains to get to Alaska in April, so I face some real trade-offs in terms of weight and capabilities…

[Taiga]

Elliot, I think you're referring to Garrett and Alexandria Conover. They wrote the Snow Walkers Companion.

[Dave P]

Sorry for bumping this, but I noticed some of these stoves are no longer available for sale.

What's the skinny on the latest backpackable stoves?

[Dan Yeruski]

WIFI stoves by TiGoat. Nice designs.

[monkey]

Bumping this again with a question on theory and practice. People do say that tall chimney is good, and even that the chimney cannot be too tall. However in application to tents I’ve seen few mentions on tall chimneys and wind; the suggestion that tall chimney can pose a problem in this regard.

So I was wondering what is the difficulty here, would it be when the pipe is sticking out too far above the tent, so that a gust of wind can “push” it dislodging the connection between the stove and the pipe or even overturning the stove? If so, what is the maximum safe distance the pipe can extend above the tent?

Or is the problem in insufficient support for the pipe, when the portion of the pipe outside the tent is taller than the portion inside, potentially causing instability. In this case, would it follow that it doesn’t matter how high the pipe extends above the tent, for as long as the portion of the pipe that is inside is of greater length?

 

 

[David Chenault]

“Or is the problem in insufficient support for the pipe, when the portion of the pipe outside the tent is taller than the portion inside, potentially causing instability.”

 

I think this is the issue.  So long as the distance between the top of the stove and the stove jack is greater than the amount of pipe outside the tent, things should be fine.

There are quite a few lightweight ti foil stoves, either in traditional cylinder or vertical oval (like the Kifaru oval or TiGoat Wifi).  You save significant weight over the pieces box stoves, but the foil does get beat up if you use it often.

[Ross L]

Yes, a pipe can be too tall as in my modified dome. I had to keep a pot of water on the stove for a counterweight when the wind kicked up. So far have not had issues with my (taller) mid that I also use my Tigoat wifi stove in. (pipe is 6.5 ft plus 9″ spark arrestor)

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