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Insulating a tent

Has anyone insulated a tent for winter camping?  I am making a nice tent-cozy of white, 200 weight fleece for an upcoming overnight here in the Midwest.  I'll report back on how it works.


Good luck with that! 
I am no physicist, but there must be a good reason why indigenous cultures of the far north choose not to employ your concept.  That alone should give pause.  Your cozy is better used as a personal or group blanket 

I see three major issues with this idea:

  1. You can achieve much better comfort results wearing your insulating articles than utilizing insulating articles made to encapsulate a tent interior.  Anyone who has tossed and turned in a sleeping bag knows you can be plenty warm inside a bag, but movement that puts you in contact with "unoccupied" parts of the bag will subject you to the cold of these surfaces and the dead air spaces not previously warmed by your direct physical contact.  Your tent may end up being a few degrees warmer, but the r-factor of such insulation will not be enough to create a noticeably warmer interior.  Furthermore attempting to warm larger masses (air volume of the tent) requires more heat, which you have not considered. 
  2. Since you are attempting to warm the entire tent, versus the relatively small volume of the air and flesh enclosed within your personal clothing, you will need a lot more tent wall insulation.  This is crazy if you are considering backpacking this set up, as it will be both much heavier, and very bulky, perhaps too bulky to even carry on one's back.
  3. Another factor addresses dew point and water vapor condensing then freezing as warm air is cooled.  As the warm air in the tent space penetrates the cozy, the temperature of that air will drop and the water vapor will condense on the surface or within the insulation layers of your cozy, causing your cozy to gain pounds of ice nightly.  This also is an issue with tents san cozy, but since tent construct utilizes only one or two layers of fabric, the ice build up can be beaten off the tent, whereas the fleece of your cozy will make deicing almost impossible.

The tested alternative is hot tent camping - tents designed to be heated by a stove designed specifically for this purpose.  If this approach sounds appealing, invest in an appropriate stove.  Backpacking stoves are not designed for this purpose.  Using a backpacking stove (or fuel powered heater) in such a manner will expose the tent inhabitants to potential carbon monoxide poisoning, not to mention the fire hazard these items present when they misbehave or subjected to a handling accident.


Kinda what I thought,  Hmm... but I'm bored so what the heck.  Not quite sure where the condensation will end up, stuck to the fleece (which is against the tent body) or out to the fly or the surrounding air.  It is a one-man tent so the size isn't great.  I think some Yurts utilize insulating layers.

I think you have to do it, Curtis, for science. FOR SCIENCE!

I do think Ed is correct here though, as usual. Won't be worth the weight if backpacking, generally. Unless you, say, construct a MYOG pulk out of corrugated plastic and Reflectix, which then broke down and became your tent wall insulation.

I agree with pillow, no turning back now Curtis, you must go forward :)

and post pictures

Polypro underwear would be lighter and probably warmer. I agree with Ed about insulating your body rather than your tent. Much easier.

You guys are the best.  You remind me of when I was a kid and my buddies would egg me on to do crazy stuff.  Even after a few broken bones I'm still a sucker when it comes to that sort of pressure.  So, as I've said a hundred times before, "Watch this!".


I know how to post pictures on my Profile, but not here. How do I do that?

Ed, "indigenous cultures of the far north" were extremely limited by a very rudimentary technology and lacked the ability to fully exploit the natural resources around them. This is why they so quickly adopted wool blankets, canvas tents and wood stoves, all of which were much lighter and more efficient than the caribou hides and open fires used previously.

That being said caribou or buffalo hide tents, or for that matter felted wool and horse hair such as you may find in traditional yurts would trap heat more efficiently than plain canvas or nylon provided there was an external heat source such as a wood stove in side. A human body just doesn't produce enough heat to warm an entire tent to a comfortable level. However, this would be impractical for the purposes of backpacking.

The Canadian Military used a thin frost liner inside their winter tents and I think Stephenson tents made a model with some sort of Mylar reflective barrier. But, these never did catch on for backpacking purposes.

But, Curtis don't let this deter you in your pursuit of knowledge. 

Yurts or gurs are wonderful adaptions to extreme cold. They use a lot of wool felt and awood stove inside. I visited one in Elko when the Mongolians came to visit. It was about 20 degrees and windy, but inside it was room temperature.

Canvas holds a lot more heat than thin nylon.  People lived year around all over the West in mining camps in canvas tents with wood stoves. They did the same in Canada and even in the Klondike.  There is nothing as warm as a canvas tent with a fire going inside, and there is nothing as cold as a canvas tent when the fire is out.

Photos of the work in progress are on my profile page.

I am using a Eureka Backcountry One tent.  

Give it hell Curtis! I wonder if one of the large hot hands body warmers would raise and maintain the temperature inside?

North1 said:

Ed, "indigenous cultures of the far north" were extremely limited by a very rudimentary technology and lacked the ability to fully exploit the natural resources around them..."

All true, but the concept of a tent cozy, regardless of materials used would not be effective, relative to other approaches.


I kind of like the idea.

Recently I down sized and bought a hybrid RV. It is a small trailer with canvas pop out beds on each end. There is a device called a PUG Pop Up Gizmo that is made out of space blanket material that goes over the canvas. It is reflective and has some insulation. It makes the inside of the trailer much cooler in the sun and much warmer at night. The same material could be used on a tent. It does not weight much and would work for backpacking just fine.

Oh and Curtis, you can't post pictures in the forum until you've made some number of posts or been around for some amount of time. (an anti-spam thing I think)


Here are linked photos from your profile:






I have a 4 season tent that is double walled (air trapped between the layers) and both walls go down to the ground.   I have seen documentaries where native peoples had large, heated double walled tents.  I think double wall tents are by far the most commonly used form of insulated tent. 

Nylon is a poor insulator no matter how many layers you have.

DrPhun said:

I have a 4 season tent that is double walled (air trapped between the layers) and both walls go down to the ground.   I have seen documentaries where native peoples had large, heated double walled tents.  I think double wall tents are by far the most commonly used form of insulated tent. 


ppine said:

Nylon is a poor insulator no matter how many layers you have.


Yes and yes!

I seem to recall that the old TNF A-frame Mountain Tent had a "frost liner" option, a "third wall" that could be hung up inside the tent. Anybody have experience with anything like that?

I have a traditional 18 foot canvas tipi made in Wyo that is Blackfoot style.  The cover is 12 ounce cotton duck. The liner of a similar material is used for the first 5 feet.  The liner goes to the ground, but the cover is about 6 inches above the ground.  The two layers provide for some insulation, but more importantly allow air to circulate through convection and out the smoke hole. A fire inside is really warm, and the firelight bounces off the white canvas. It is a glorious way to spend the day during a snow storm.  Native American evolved a style of living that is hard to beat.

Curtis, I applaud your inventiveness and look forward to the results. As others have noted, insulated tents have existed(still exist) in some primitive cultures. The Touregs of North Africa still use tents of wool or hair. One critical issue I see, is how your tent vents. By that I mean, is this a goretex tent or a nylon tent with a fly, or a single layer coated tent. The latter, would, I think be a disaster. Condensation from your breathe would gather on the inside of the tent, as well as your insulating layer, which will then become a wet rag. Goretex would be the best option, as it will breathe. My old Bibler Impotent had fuzzy goretex on the inside to capture condensation which would then evaporate, rather than trickling down the inside of the tent. The canvas and wool tents mentioned, breathe very well. In fact, the Toureg tents has quite loosely woven. One person mentioned a frost liner. I have used these in the past, but they don't so much provide an insulting layer, but a way to catch condensation, much like the fuzzy goretex. In the later sixties, REI sold a very small and lightweight double wall tent made from dacron. Supposedly, it had been tested in Greenland. I think that such a tent would provide some level of insulation as the two layers trapped air so in wind there would be more insulating effect.

Ok, I know a little about this. One year on a scout trip, I had to take over a summer tent. My nice,wonderful,cozy, NEW three sesion tent went to the cub scouts. Yes a wonderful mother did't lission. And informants me her son has a new tent. The temp that nite stopped to the mid teens. After seeing what this kid brought.arrrr, anyway I wrapped the tent with a tarp the wind was wipping up good. The inside of that orzark trail tent was covered in ice from my breath. And the cozy part was I put on ever live of clothing I had. For the cars. Yes as in the kids movie cars sleepingbag. The same ones kids get cold in them in side. I never led another camping trip for the cub scouts with out doing equipment check before leaving again.And if my tent was cozy. What would I brag about? To me it's half the fun. Happy trails

If I learned anything in making a tent-cozy it is that the mid-winter temperatures will soar, nearly 50 degrees expected tomorrow, night-time in the high 20's and 30's, crazy warm for the Midwest.

So, the dog-gone thing is ready to go.  I had to make collars for the mesh sleeves near the top where the poles slide in, there was a gap.  With an expected low of about 15 on Wednesday night my plan is to try it out then.

I'll monitor inside and outside temps with the same thermometer we use at home showing both at the same time.  Fun, fun.

I'll report back after the trial.

Interesting concept. Not sure how effective it will really be.

For the same weight you could put a small wood stove in the tent. Now that WOULD make a difference.

But the cozy could be multiple use, Rambler, if it replaces a fleece jacket for in-camp insulation...

Pretty sure this would end up weighing the equivilant of like 4-6 fleece jackets.... if not more. For a pound and a quarter or so you can have a nice wood stove =P

Good point. I'm on-board with wood stoves, btw...I just wish my ammo-can stove weighed 20 ounces!

Might have to give Josh over at Ruta Locura a call...

I'm in the woods right now. Temp 15.  Hanging by the fire, I'll have the first test results in the morning.

At 2:00AM in the tent 29 degrees, outside 9.  5:00AM 27 in, 5 out. 

Frost is on the inside of the tent walls that are nylon.  The fleece covered netting sections are frost free. 

Find this interesting keep playing this out and post more as the info comes to you.

Right?! I am very intrigued. They say a full double wall tent can add up to 10 degrees to the rating on your sleeping system, when fully buttoned up. Preliminarily, the cozy appears to add 20 to a tent with a mesh inner...

Edit: And not even a full rain fly!

Hey Patman, could you help me again with photos?  There are four I would love to post here from my profile.  There is one of the tent, one of tent with cozy, another of cozy and fly and lastly from inside showing the frost on the tent wall.  Thanks brother.

I have questions now.  Did the fleece block to much air movement causing the frost on the nylon walls?  Why was there no frost on the fleece covering the netting portion?  Would a more fully bug netted tent with a cozy be warm and frost free?  Should I double up on the fleece covering the nylon walls?  What would a tent made of fleece be like?

Best of all I had an entire state park to myself.

The fleece more than likely did block too much air flow, however even with good air flow frost/condensation in winter time is all but inevitable to some extent. This is very common, the frost on interior tent walls in winter.

Simply put, your breath and body moisture condensed on the nylon and froze due to the temperature. The same done above freezing would result in wet beads of condensation.

The reason there is no frost of the fleece is because fleece is rather air permeable and it was probably able to dry a rate fast enough to offset the moisture rate. The reason it froze on the non mesh sections of the tent is because those sections did not have adequate air flow and so the water moisture froze on the first contact that was at or below the dew point.

Yes an all mesh tent would probably be frost free, but it would also probably not be as warm.

A tent made of fleece would be heavy =P I find this experiment interesting for sure, just don't see the practicality of it. You'd be better off wrapping yourself in the fleece for extra insulation.

Curtis, as I asked and alluded to in my original post, the issue is breathability. I can't find that you responded with the type of tent(Goretex, nylon with a coated fly, coated nylon). Regardless, water vapor in your breathe passed through your liner and formed on the cold underside of the tent. If you have a small tent, you increase the heat generated by your body. However, you also exhaling a lot of water vapor. The Impotent I had got around this problem by having the inside of the Goretex lined with a  fuzzy material that would catch the water vapor and allow the Goretex to gradually release it to the outside. With more air circulation, the water vapor in the tent would evaporate more quickly and therefore less condensation on the inside. But more air circulation to the outside means a loss of heat. Comparison to modern home construction might lend some insight. A 2x4 wall will have insulation between the inside and outside walls. Further, the inside wall is normally painted with a vapor barrier paint. This keeps water vapor from entering the the space between the walls and forming on the insulation. As well, the insulation itself has a vapor liner on the inside and insulation companies are very careful to point out which side faces the inside. Now, if you had two different materials, one slightly less breathable than the other, and put the less breathable one on the inside, and the more breathable on the outside, with enclosed airspace between, you might have in insulated tent without the condensation problem. This may be why the dacron was used in the Greenland tent I mentioned.

As a practical matter, the small backpacking wood stoves have little volume. They do not hold a fire very long. It is hard enough with a full sized packer stove in a wall tent to keep a fire going.  Tent insulation works all night. It makes a difference in that 0400 coldest, darkest part of the night in cold weather.

Erich, if memory serves me correctly, the fuzzy stuff you mention was called "Nexus". 

As ppine mentioned a sheet metal stove without fire brick does not hold the heat as well as one with. On a recent winter trip for work we had canvas tents and sheet metal stoves. I didn't sleep at all because people kept on banging the door of the stove while feeding it every hour.

While I really enjoy a fire while winter camping I still prefer adequate clothing and an exceptionally warm sleeping bag to anything else, including an insulated tent.

North is right. A wood stove is wonderful for drying out and getting warm after a day in the bush. You can dry out your clothes and sl bag. But it is difficult to rely on it after the fire goes out. Better to plan to sleep in the ambient conditions.  You will be warmer because you will be drier.





North was Nexus a material that was separate from and added to the Goretex? The Impotent I had, was one that Todd made for me in about 1980 or so. It was before he started Bibler Tents and was sewing them in his apartment. It was yellow Goretex. Though a little fragile, it was the best tent for its purpose I've owned.

Way back in 1980 when I was winter camping in Yosemite, I had a friend who was an employee in Curry Village which is in the SE side of Yosemite Valley where the sun never shines in midwinter. He lived in a tent cabin and hung wool blankets on his walls i=on the inside. It was heated with a wood stove but just the cotton canvas let most of the heat out. His tent was always toasty.

I used to winter camp in the Grand Canyon and made a insulated cover for my sleeping bag from a wool blanket by sewing it down the long side and across the bottom, then pulled it over my bag, I stayed much warmer.

You can use sterno cans to help warm the inside, they burn clean with no carbon dioxide poisoning.

Gary, Sterno does produce carbon monoxide and is very dangerous in an enclosed space. Also, being alcohol, it produces water vapor when it burns. I would not recommend using it inside a tent unless the tent is well ventilated. Glad you survived.

I used it many,many times in the 20 winters I backpacked the Grand Canyon. I camped there 3-6 months of the year from 1983-03.

I don't doubt you have done it, Gary. But here is an article about the danger.

There are many others on the internet. Any time you are burning something, gas stove, wood stove, etc. in an enclosed space with poor ventilation, you are breathing carbon monoxide. If you go to the Sterno website, you will also find cautions about using their product.

I recall using a propane fueled lantern to read in my tent while trapped during a freak May snowstorm on top of Mt Palomar many years ago. It definitely warmed up the tent, but even though I opened the door once in a while to refresh my air supply I still wonder that I didn't either suffocate or set myself on fire.

My point is that just because we've done something and survived doesn't mean we should do it again Gary :)

small propane fueled devices arnt a danger in enclosed spaces. A tent is by no means air tight. If propane devices were an issue everyone that has a propane stove and or oven in their house would be dead and we would hear stories about it all the time. It is definitely not a bad idea to partially open the tent door to allow better air flow, but it's not necessary from a safety stand point. They even sell propane room and tent heaters, because they are safe to use in enclosed spaces. They were still safe long before they added the catalytic devices to them.

The big issue with using a stove inside a tent no matter what the fuel source is the danger of fire and or a gas leak.

Not all fuels are created equal in regards to safety in enclosed spaces. So do your research first.

Don't believe me? Set up your tent, put a propane heater or stove inside the tent and turn it on. Also put a CO detector in your tent, hanging from the top or somewhere other than just laying on the ground. Sit back and wait for it to go off. There are literally millions of small homes, RVs, mobile homes etc that use propane for their stoves. Unlike other propane appliances like fridges, dryers, water heaters, etc stoves are not vented outside. Believe me, if using propane indoors was an issue you would know. There are warning labels on everything these days, some of it is legitimate, but most of it is just liability mumbojumbo ramblings from the manufacturer.

If it snows during the night the bottom of the tent and the fly can get sealed to the ground. CO kills people all the time.

I try not to tell other folks what to do, so I won't say you can't burn whatever you want in your tent. Just saying I look back on that trip and marvel that it didn't turn out worse. Sort of like the night I woke up walking down the center line of a state highway after falling asleep while walking next to the road.

You can do stuff like that, but the odds may catch up to you if you do it often. As for me, I use electric light and insulation to keep warm these days since those things are less likely to kill me. Well and I stop walking when I need to sleep now too :)

Rambler, no doubt your occasional venting was sufficient to prevent CO poisoning. However, by saying that you don't need to vent, only opening to increase air flow is simply not true. Everyone has the responsibility to make their own choices, here. But to advocate to others that using a stove in a tent for warmth is perfectly safe from a CO standpoint, is like advocating that a handgun is the best defense from a bear. I will leave everyone with just a couple of cases of deaths from CO poisoning in tents.

Many of us have spent time in cozy wall tents with a wood burning stove. They work well. But they are also not tightly sealed, and they vent to the outside. A propane heater, gas heater, lanterns, etc. vent to the inside of the space. If you read the article posted, you will find that a number of people in the period noted, died from CO poisoning, specifically in tents. Again, advocating that it is perfectly safe is dangerous advice. We should remember that there are newbies on this site asking for advice. As well, many people research this site from the web. I would hate to learn of a fatality from information gained on this site.

Isn't Rambler just basically saying "Rather than speculate and ponder, go see for yourself."?

If I'm wondering at what temperature water boils I could read a bunch of web-or-actual-pages, or I could put a pot of water on the stove and throw a thermometer in it. 

And back on-topic, I'm definitely thinking of doing up a cozy for my Akto...

pillowthread said:

Isn't Rambler just basically saying "Rather than speculate and ponder, go see for yourself."?

If I'm wondering at what temperature water boils I could read a bunch of web-or-actual-pages, or I could put a pot of water on the stove and throw a thermometer in it. 

And back on-topic, I'm definitely thinking of doing up a cozy for my Akto...

No he said if you think doing that is a bad idea prove yourself wrong by doing it. I've spent enough time leaning on both sides of a bar to recognize that as a dangerous suggestion, though I've seen more than a few folks think they can win that sort of bet.

As for insulating your tent, unless you are putting a stove inside it doesn't make sense to me. Airflow is what prevents frost build up and the cozy inhibits chimney effect. Depending on where the frost line is, you are going to build up ice somewhere. Looks like the pics posted show that inside the tent body on the wall, but it could range from there to the cozy or the inside of the fly depending on outside air temp and how warm you get the inside of the tent.

I prefer to keep everything as open as possible including the tent doors if the wind is low enough. My goal is to move the moisture rather than retain heat. My quilts do that job and keep my body warm which is all that matters. If they get wet though they may stop working and then I've got a problem, so moving vapor as far away from them as possible is more important to me.

We all want the same thing: to move the moisture. I'm super cool with the frost collecting on the inner tent if that's what it wants to do. That's where I want it, as opposed to in the cozy.

I've got a wonderful VBL that Integral Designs made a number of years ago which does a splendid job of keeping most of the water vapor I produce out of my sleeping insulation. The vapor that does condense in my bag is mostly from my breath, and that vapor condenses because it hits a shell fabric cooled by the outside air. If I can raise the ambient temp by in my tent by 20 degrees with a pound of fleece that doubles as an in-camp wrap, that seems like a good deal to me.

The raised ambient temperature will mean less vapor condensing in my sleeping insulation, which can hold a lot of water, and more vapor condensing on the inner tent, which can not hold much water. If my worst problem becomes wiping up condensation with a bandana, as opposed to trapping it in my bag, that's a worthy trade off.

In other words, Curtis is my new hero!

Back to the topic. Vapor barriers do work. But they needn't be as heavy as fleece. Hence the Goretex with the fuzzy lining on my old Impotent. The fundamental issue is to keep as much heat in as possible and let as much water vapor out as possible. Being in really cold and dry conditions is relatively easy. Being in 30 degrees and very wet(think Hoh rain forest) and the problem gets harder. A cotton tent will tighten up in wet conditions. That lets much less water vapor out. If it is dry the cotton breathes. Really, what we need to get back to, is the multitude of tent designs available, going back two hundred years or more. Rather than thinking that each one is acceptable for a range of conditions, we need to accept that one must have a variety of tent designs and materials for the range of conditions we are likely to encounter.

I agree with Erich, just like clothing we choose our shelter based on the conditions and in my case my wallet as well.

Winter-time tent condensation and icing seems to be a separate but related issue from the inside temperature.  Now I'm thinking of figuring out how to vent my breath yet keep the heat.  Maybe a CPAP type of face mask?  

Another topic, maybe another forum post for the future.

We need like Bat-signals to get Tipi and OGBO in this discussion...hell, Bill's probably in Antarctica right now wearing such a face mask...

One design(not really a back packing tent) that does a good job of ventilating and working well with a heat source, is a Baker Tent, or the modification that I use, the Mason Tent. I have two of the latter, a 5 X 7 in nylon and a 7 X 7 in Egyptian cotton. The latter sleeps three easily and can sleep five, the additional two in the canopy area. Although made in cotton, the weight is 12 pounds, without poles, which admittedly are a little heavy. However, there is a similar design that works quite well and the weight can be reduced to about 4 pounds, also in Egyptian cotton. This is the Whelen Tent, designed by Colonel Townsend Whelen. Any of these reflector tents, despite being open at the front, reflect heat downward to the sleeping area. I have used my cotton Mason tent this way, and it is surprising how much heat can be gained with even a small fire. With the awning extended on both the Whelen and the Mason/Baker, heat can be trapped.

No, I am not in Antarctica right now (it's "dark time" down there right now). These days, I am very occupied with running several training courses, one of which is for adult Boy Scout leaders to prepare them to take groups of youth SAFELY on winter camping trips involving heavy snow and sub-zero temperatures (male and female - BSA is co-ed for youth ages 14-21, putting it in line with Scouting in all but 1 or 2 other countries in the world with Scouting organizations). The other is also training adult scout leaders to SAFELY introduce the youth to rock climbing.

Curtis, as is typical and standard on the web, the information posted in this thread is a mix of accurate, useful advice and (sorry to be blunt, but if the shoe fits, just ignore what I say), very dangerous information.

First, if I pick just 3 of the responders, Ed "Who Me", North1, and Erich have provided accurate information, coming from many years of experience in serious "polar" or high altitude situations.


I took this photo during a Winter snow training outing. The tent's occupant was adamant that he would not sleep in a snow cave, igloo, or any other shelter that put him under the snow. This was about sunrise. The underlying tent is a 3-person Sierra Designs expedition "Stretch Dome". In the morning, I went to the tent and called out to its sole occupant. He did not answer until I brushed some snow off the vestibule (snow dampens the sound extremely well).

Actually, an igloo, quinzhee, or snow cave are all quite warm, with the inside being around 32°F (or more if your snow shelter has 2 or more occupants). The snow breathes quite well (unless you overheat the inside and let the shell freeze - in which case make sure you have a vent hole)

Many years ago (about 1962-3 IIRC) a couple friends and I acquired an Eddie Bauer Himalayan Expedition tent (this was in EB's earlier incarnation as a purely mountaineering supply business). The tent was 3 layers of A-frame - the outer fly, the main A-frame tent, and an inner "frost liner". The two vestibules had a small zip-out hole in the floor of each vestibule for (1) scooping up snow to melt for water and (2) at the opposite end, for burying "human waste". Because of the storm we encountered  in the Sierra, we stayed put for 3 days (except for an occasional exit to dig the snow off the tent).

We did NOT have a heating stove in any of our tents.

By experience over about 60 years that included snow outings, the best way to stay warm in your tent is as follows:

1 - insulate your own body by having:

     a. a sleeping pad under your sleeping bag - the pad should be closed-cell foam,

           which can be in the form of an inflatable pad that encases closed cell foam (e.g.

           a Thermarest pad) or other pad that strongly restricts air circulation within the

           pad (e.g. the multiple tiny chamber NeoAire or a Primaloft-filled pad such as

           the Big Agnes Double-Z)

     b. a top quality sleeping bag, rated to 10° colder than the expected low temperature

             (the sleeping bag can have a synthetic fill in moist climates or high quality down)

     c. ventilation for your breathing through the "face hole" of the sleeping bag,

     d. plus wear a good set of long johns as "pajamas" and do not sleep in your wet,

             sweaty clothes. Patagonia, Helly Hansen, and several other companies

             make excellent "warmth layers" that will substantially increase the warmth

             of your sleeping bag/tent combination.

2. - ventilation of the tent through small, mesh-covered vents. Large stretches of mesh

           will just allow your warm air to flow out easily, dropping the temperature


Alternately, if you want to use a heating device that involves a chemical reaction, such as a stove which might burn wood or some compressed gas, you may want to consider a tent such as the Arctic Oven, pictured below.
DogTent2.jpg My wife and I used this tent during a dog-sledding visit to the Alaskan Bush. The tent is double-layer and has a wood-burning stove (note the wood pile in front of the tent). A HUGE CAVEAT, however. As noted by several of the posters in this forum, ANY TIME YOU BURN fuel, whether wood or a petroleum fuel (propane, butane, white gas, etc.), the combustion requires oxygen (which depletes the oxygen available in the tent for you to breathe) and produces several gases, notably Carbon Monoxide (CO), and Carbon Dioxide (CO2). The presence of CO2 reduces the capability of your human lungs to absorb the oxygen (O2) from the remaining air. CO is a poison that acts rapidly to kill humans (and dogs and canaries). If you have sufficient ventilation, you can take in a small amount of CO or CO2 without dying. However, cases such as Admiral Byrd (who almost died in his cabin in Antarctica before one of his crew checked in on him) are all too common.

This tent does have a wood stove inside. It vents through a stove-pipe that extends through the roof of the tent (which has a section of material in the roof that is non-flammable - though that did not prevent my melting hole in a nylon jacket, when I carelessly just brushed the stove).

I would STRONGLY DISCOURAGE USING ANY tent/stove combination that is not purpose-made by a known, highly experienced tent-maker. It is too easy to screw up or fall asleep (perhaps by CO in the air) in the tent until it is too late.

You can set up a tarp that is slanted with a reflector fire (pile of rocks with the fire facing the lean-to tarp to reflect the heat toward the shelter - there are tents built to this configuration - Baker and Whelan lean-tos) - plenty of ventilation, plenty of heat directed into the tent.

If your tent is sized to hold just the number of people in the group (1, or 2, or 3, or 4, ....) has some ventilation, plus everyone has an adequate quality sleeping bag (if your group includes couples, they can get 2 bags that zip together and conserve heat by cuddling in the double bag), then you can all stay warm enough.

By the way, someone above mentioned an Ozark tent - tents from "Big Box" stores, like the Ozarks, are pretty poor quality. I would strongly avoid such tents for cold weather camping.

i have a few observations.  

-3 main battles we fight in terms of sleeping out in the cold - staying warm, having adequate shelter from the wind, and dealing with snowfall on the tent.  needless to say, both wind and snow require a tent whose material and poles are study enough to stand up to the elements.  warmth, for me, is something i get from clothing and sleeping bags; can't ever recall waking up in a tent in -20 degrees and having the interior feel warm, even if it's packed with people and gear.  if anything, tents that are full tend to have more rime falling on the sleeping bags, frozen condensation.  i have never insulated a tent; i always insulate my sleeping bag from the snow with two sleeping pads.  

-one way to help your tent do its job is to dig in - either build a short wall with blocks of snow or dig lower so your tent is at least partially protected from the wind.  

-i have dabbled with snow caves and igloos, all early in my winter hiking life, always in winter camping classes when i was learning the ropes.  both are good options if done well; neither is something i would try without taking a class or learning from someone who knows what they are doing.  

-heat sources and modern tents can be a very bad combination if you aren't careful.  carbon monoxide risk already discussed above, and nylon tents and sleeping bags tend to melt pretty quickly when exposed to heat or fire.  i cook outside.  another reason to build that snow wall or dig in.  

A Baker or Mason tent is really good on a fall canoe trip.

Nearly all of the people that ignore the idea of a fire and a shelter together have never tried it.

Thread drift much people LOL I am interested in his post...Have no idea why this changed things...LOL

Well the thread has a broad title, and then Curtis necked it down in his OP to be about the cozy idea, so there's a bit of contradiction there.

Curtis is still learning the ropes here, so let's enjoy the freedom, within reason. Now, if Curtis wants to rein things in, it's his thread.

Back on topic I'd love to know the weight of your cozy, Curtis, if you've got a scale handy...

This is like the hot-stove league in baseball. Winter, snow and cold and a bunch of us shootin' the poop.  As far afield as this has wandered it has in fact focused my thoughts.

If I need a shelter from snow and wind a tent is the place to be.  If all I need is sleeping warmth then a warm bag, a good pad and a bivy sack will do just fine.

Some of what I've learned here was helpful but conjecture can not take the place of actually camping in the cold.  I intend to do something, fail and do it differently next time.

I started this post because after searching on-line for any information on insulating a tent the best I found was someone putting leaves around his tent.  

I don't own a scale, never been much of a weight-weenie (that's what bike mechanics call their customers), and I think weight is just one of many factors to consider.

So I lay down a challenge.  Insulate a tent in the way you think will help, write about it here and we might find a common solution. Post both failures and triumphs and this will help us all.

Curtis what have you taken away from your experiment?

An insulated tent can work. The temperature inside was higher than I would have expected.  

All internal frost formed on the nylon walls of the tent, the bug netting was frost free, this when both were covered with fleece.

A fully bug netted tent with fleece might be the way to go but who needs bug netting in the winter?  A tent made of fleece with a full fly cover could be the solution.

Curtis Evans said:

An insulated tent can work. The temperature inside was higher than I would have expected.  

All internal frost formed on the nylon walls of the tent, the bug netting was frost free, this when both were covered with fleece.

A fully bug netted tent with fleece might be the way to go but who needs bug netting in the winter?  A tent made of fleece with a full fly cover could be the solution.

Did you measure before/after weight of the cozy? Frost on the tent wall does not mean the cozy did not also became a settling place for moisture.  In fact one should compare the before after/weight difference of your tent system, both with and without the cozy (use the same tent).

As far as the warmest, most comfortable LW shelter in snow, it would be a shelter covered in snow.  The image Bill shares of the snow covered tent probably is noticeably warmer than the same tent without the coating of white stuff.  But I would not recommend piling snow on one's tent, as the tent will sag and become cramped, and possibly incur damage from the weight, not to mention a pain to de-ice.  When time, terrain and snow pack permit, I will always opt for a snow cave or igloo.  But I still carry a tent just in case, and I also bring a snow saw to facilitate making these shelters.  In the lower 48 these shelters are often warm enough you are comfortable lounging in base layers and a light insulating layer (e.g. wool shirt and pants).  But if you are in truly cold weather (sub zero) you will need more layers.  Regardless, snow shelters are definitely the warmest LW solution. 

And please, everyone, don't use a stove in a tent (hot tent systems excepted).  When things go wrong people are poisoned and wake up dead!  Certainly if we can tolerate cooking outside in the weather shown in the image below, then so can you.  If that sounds like too much to ask, then perhaps you should not be out there in such conditions.

Pictured: two people and tent riding out a ground effects blizzard, while cooking dinner @ 3:30pm, OUTSIDE: Mt Langley @ 13,500’ late January, air temp: -6°F (day time) wind speed: ~45mph.  The wind chill equates to something between -40 and -60 F, depending on the method used to perform the calculation.  We pitched a tent instead of digging a shelter because the snow lacked sufficient depth (24") and we weren't able to scout an alternative, avalanche safe location, given the limited visibility.  It ended up being a sundowner wind.  If the wind would have continued, we would have erected a revetment around the tent for additional protection.  The next day was a bluebird summit day, cold air temp, but no wind, clear skies with a hot, direct sun.



Ed, your winter camping experience goes far beyond anything I have done, I bow down to you.  The best part about a forum such as this is my chance to learn.

Weighing the tent cozy before and after use is a great idea but it might have to wait 'til next winter, the midwest is already leaning toward spring. 

What is your opinion on candle lanterns inside tents?  UCO states the BTU's given off of their lanterns.  Do these provide adequate heat for a tent? Are they safe to use regarding Co2?  

Have you ever recorded in-tent temperature compared to outside during any of your adventures?

A bunch of question marks here but as I said, I am learning.

Curtis, I would note that the testing you did was with a single tent. To get a somewhat accurate test, you will want two identical tents, one with the cozy and one without. This will still be seat of the pants science, but you will have a better idea of the benefits of the cozy.I would also argue that reason the bug netting didn't have frost on it was the water vapor passed right through it. You do not need more bug netting, you need a tent exterior wall that is more breathable.

I'd still want a fully-enclosed inner tent. A fleece inner would serve the same as a mesh inner with regards to air movement; yes it would be more breathable but any gust that got past the outer tent would also go right through it.

I think a nylon inner is the place to start, but now I'm thinking about fabrics like Polartech's new Alpha in an application like this. Alpha is exactly what we're talking about here: a nylon face fabric with a CFM around 40-50, and a light, warm fleece layer. 

I wonder if the right weight of fleece cozy would work to wick & evaporate moisture from the inner tent, in the right conditions. Not unlike Alpha, or Paramo...

Erich, a side-by-side test would be awesome, but alas out of reach for my wallet.  Bike mechanics love their work but it just doesn't pay much.  If anyone has two or more of the same tent maybe they could try insulating and testing.  Twins, one in each tent might lessen the difference in sleepers, breathing, body heat etc.

Mr. thread, or may I call you pillow, have you actually seen and felt Polartech Alpha? Their web-site shows that it could be the material to use.  Imagine a tent made of that material with a standard full fly cover.

It would be great if anyone has any industry connections that might want to work with this idea of an insulated tent.  My hand stitching is rudimentary at best, skilled people might create just what I imagine.

Thanks for all of the input, this is fun.

Ha! This is great. Yes two of the same tent, and a set of identical twins who have consumed the same food over the previous three days. 

Curtis, most folks here call me 'pillow'. As far as commissioning someone to make a prototype for you, the only guy I can think of is Roger Caffin. He posts pretty regularly at

I've handled a garment made of Alpha, but haven't used one. Other folks who regularly post here, have. There is Alpha Direct, with just one side covered in face fabric, and the original Alpha with both sides covered. I want to say the inner fleecy part comes in four different weights?

Candle lanterns in tents...

They can be a hazard, it is the nature of the beast.  But mostly I found them a nuisance as my tent mate knocks the thing, getting wax everywhere.  But I will use one when soloing, not to provide heat, rather to accelerate a draft through a roof vent, effectively venting out the moisture.

As for candles for heat: they output around 1800 BTU/Hr., about the same as a human body.  As for trapping heat in tent: the inside/outside temperature difference can vary wildly.  Camped on a sunny, snow field in single digit temps the tent can be toasty, like a sauna!  But night time differentials tend to be 5 - 10F in my experiences.



You wouldn't need twins. My point is that a single tent with cozy on one night and without on another night will not be accurate in the least. You could easily set up a benign heat source, like an incandescent bulb in each tent and measure inside and outside temperatures.

Good work by Curtis. 

Would space blanket material be a better light weight alternative to fleece?

It works well on the tent ends of my hybrid trailer.

Space blanket material is better at reflecting radiant heat, it does not have the insulating quality I was looking for and it would block the transfer of moisture completely causing excess condensation in a tent. Columbia makes clothing with a patterned reflective inner layer that has holes to allow moisture out.  That might be a possible material to insulate a tent.

My comment on twins was a poor attempt at humor, sorry if I angered anyone.  Any test done without humans inside the tent would also need to supply water vapor to replicate breathing and perspiration as well as drying clothing.  This would need a "Myth Buster" level of testing but it could be done.

 There doesn't seem to be any attempt by the manufacturers of tents to supply us with warmth ratings as in sleeping bags and clothing. For that matter air flow, ventilation, while mentioned as a marketing term is not quantified using any HVAC type of measurement.  

I don't know if this is allowed in these forums but I would love it if tent designers and manufacturers would chime in on tent insulation.

I have no expectation of a "warmth rating" for a tent.  A tent keeps out moisture and wind.  My clothing, sleeping bag, and activity level keep me warm.  If I want insulation, i would dig a snow cave or similar.

Insulation is heavy, and this is a lightweight forum....

Reflectix is another material to consider.

I broke down and bought a scale from my local Ace.  The tent-cozy I made weighs 793grams/1lbs12oz. 

Dang, now I gotta weigh all my stuff!

DrPhun said:

I have a 4 season tent that is double walled (air trapped between the layers) and both walls go down to the ground.   I have seen documentaries where native peoples had large, heated double walled tents.  I think double wall tents are by far the most commonly used form of insulated tent. 


Thats how military tents are, there are hooks inside the main tent to which you attach a liner. It drapes between the hooks to leave air spaces, and being made of white canvas it really brightens things up inside. 

So many things to comment on-

First, Curtis- I think this is clearly an interesting experiment. Do I think I know the answer to how it's going to end up? Of course, 1 3/4 is a lot of extra down insulation you'd be able to carry which would be far warmer. BUT with that said, the experimentation is the most interesting part to this, theres always a way to reinvent the wheel, it doesn't always work better though. It sounds like half the fun (for you, and those of us who get to learn from your testing) is the tinkering, so rock on!

DrPhun- a double wall tent is not an insulated tent, far from it. It helps reduce condensation on the inner, and can keep sideways winds, rain, snow out but it's not much warmer.

Hikemor- Trailspace is not a lightweight forum at all. There's many different types of people and approaches to enjoying Mother Nature and the best part about this site is that it has always welcomed them all.

Hey Curtis, 

   Don't know what your budget is, or how far you've gotten. But the best lightweight material in a workable format is aerogel. Its a silica derived material, and sadly is still largely used more by the scientific community, hence the price tag. But it is available in sheets/blankets that might serve your purposes. Using it in the floor and main walls would be my recommendation, having vents or breathable entrance material would be a good idea if seeking to reduce moisture. Think along the designs of a tarp tent while making what is normally a scene enclosure, the insulated area.

Aerogel, WOW!  Expensive as all get out but quite an awesome insulation with possibilities for all sorts of ultra-light backpacking items.  Thanks for the tip.  They even sell a jacket on the  site.  

Has anyone here ever worked with this material?  Would it be appropriate for use in the outdoors?  Does it pack small?

Aspen Aerogels incorporated it into a sleeping pad and some jackets a few years back. Needless to say, it never progressed, probably due to the cost. 

I think aerogel is a non-starter in this application. Too cost-prohibitive, among other things like workability and longevity.

The more I think about it, the more I really like Polartec Alpha for this hypothetical MYOG inner tent. An inner layer to collect condensation/frost, a super-light-and-super-resilient fleece middle, and an outer layer to shed wind and mist. Most permutations clock in around 40 CFM, which is really quite breathable.

I'm not sure where the inner layer would add anything but condensation inside the tent.  I do like the idea of Polartec Alpha as a wall with a stand-off outside impermeable shell. I would also imagine a bath-tub floor attached to the Polartec walls.  Does anyone know of  any small scale custom tent makers that they would suggest?

Whew...there sure is a lot going on in this thread. I'm not 100% on the insulated tent idea...but I like deviant research trajectories (they tend to proceed scientific revolutions) so I will chip in.

I am in agreement with pillow. If you're not going to create insulating walls from a roll of lightweight painter's plastic and duff (I'm sure some Bushy folks have played with this idea on Youtube)...synthetic insulation wrapped in nylon seems like the smarter move. Synthetic insulation cost a little more...but fleece insulation is best used when high "breathability" is an important factor (on the body usually...though is summer its drier than other bags).

As far as ventilation I would opt for adjustable vents (like on snowtents) rather than hedge with breathable walls. If (its a big if) the insulation manages to raise interior temps as much as 20 degrees there will be sufficient thermal power inside the structure to produce good ventilation.

I looked at the postings so far and came up with some rough numbers. Here are the solutions posted so far:

   Warm clothing and good sleeping bags and pads,  13 mentions

   Added heat source, stoves etcetera                       11 mentions

    Double wall tents                                                   6 mentions

    Snow caves                                                            5 mentions

     Tent cozy                                                               3 mentions

      Space blankets                                                       2 mentions

The concerns were weight, bulk and condensation/icing.

My solution for a warmer winter tent:

1.) Use the smallest double wall tent available. They are easier to heat. I use my Tarptent Moment DW (ripstop interior) when I go solo. My Tarptent Scarp 2 for two person camping. 

2.) Use a groundcloth. A painter's cloth won't freeze to the ground or let your tent floor freeze to the ground. I avoid Tyvek ground cloths in winter.

3.) Vent as little as possible. This keeps more warm air in the tent but remember to vent enough to keep excessive moisture/frost from building up inside the tent. Close upwind vents and open downwind vents.

4.) Use a candle or oil lantern. These will heat up a one or two man tent nicely. Be sure to put it out before going to sleep!

5.) Place outerwear clothing under your mattress. This provides extra insulation and saves space in the tent.

6.) Place shell parka over the foot of your bag. Zip it up and cinch down the hood. This will keep the foot of your bag warmer and, most important, dry if (when) it touches the frosty tent wall.

7. Set tent on packed snow. Pack down tent area with skis or snowshoes, let set for 1 hour and put up the tent. Snow is an insulator.

8.) Allow fallen snow to stay on the tent fly. Again, snow insulates the tent.

Good winter tents have a fly that goes to the ground to protect against wind and spindrift snow. ANCHOR tent flys with stakes or deadman buried in the snow that are attached to sewn-on stake loops at the fly hem. Four to six fly hem stake loops are needed. This prevents fly flapping in high winds and ALSO prevents built-up snow that has slid off the fly from pushing the fly inward.

Eric B.

hmmm, Dakota fire pit with packed in chimney? not "Leave no Trace!"....

reflected fire radiance would be the closest/best way to heat a bivy sack on steroids!

and then it could be catastrophically too hot for the fabric....

mylar, & lean to, with reflected fire / or new tech fabrics? 

"Down next to the body" is better than empty air anytime!

and with the new Down treatments life is good! from what I hear anyways....

In latest Finland trip our family faced too cold weather for our equipment, very unusual for May. Our sleeping bags were rated for -1 °C, while there were -4...-5 °С during two nights, so the temperature fell into "risk" range. Also our Kaitum 3 tent was too large for such a cold weather (we should have taken our Abisko Lite 3 tent), and we didn't have warm enough sleeping pads. 

We invented a know-how for insulating the tent by simple unbuckling its upper part at foot end (initially the tent is symmetrical). I tightened the clothesline to avoid the ceiling from falling on the floor, so the result was very much like "conical" tunnel tent. That reduced the internal volume, so the tent appeared much warmer for us. 

Here are the photos:


Luckily we also had two fleece liners for our sleeping bags and two soft bicycle cases made of 240D nylon which we laid under the tent for increasing the warmth.

October 25, 2021
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