I've mentioned before that I want to try using tea candles to heat my tent. Yesterday my wife found this article on using them to heat a small room:



That's encouraging. It's pretty chilly here today and will be below freezing by 7:00 pm. Perfect nasty weather to test if a tea candle heater can warm my tent. To be clear, my goal is actually to warm my sleeping bag and pad inside the tent. I'd blow out the candles and put the heater outside before getting in the tent.

That may be wishful thinking but I have to try it.

If anyone has any thoughts on this I'd love to hear them and if I can I'll try them out this evening.

I don't know anything about this way to heat but I do wonder about the C02 output and whether you'd experience any problems or not. Just a thought.

That's all for now. Take care and until next time...Be well.

snapper

The heat of combustion of paraffin wax is around 42 kJ/g so it is a pretty energy dense fuel source. Much more dense than typical fuels used in pop/cat can stove (Methanol = 19.9, Ethanol = 28.9, iso-propanol = 30.5 kJ/g). Of course actual heat released will depend on the efficiency of the system, but on paper it looks like a reasonable choice.

The guy uses pots to prevent the heat from being radiated away. The objective is to get the outside of the pot temperature to be as cool as possible without restricting airflow into the candles. You don't want all of your heat going up the chimney either. I am thinking some locally sourced rocks to absorb the heat and two (or maybe 3) layers of aluminum foil as a radiation shield.

Keep us abreast of you tinkering!

I have used candles in my 10x10 canvas tent to little effect, a hot water bottle works so much better at heating a sleeping bag.

Heck, use the candles to heat things up, and the carbon monoxide to help you fall asleep. Triple use, heat, light, sleep aide.
Duane

Well I didn't make it to the store to get candles until it was late and then had to work some more when I got back, so the test will have to wait until later today.

I did however get a chance to build a little heater like you described using rocks and a radiation shield and it worked great. A huge amount of the heat was stored by the rocks.

The top of the rocks peaked at about 117º after about 30 minutes and anywhere else you could touch the heater was cooler than that. Plus, the rocks stayed warm for quite a long while after I put out the candles. They were still emitting a lot of heat well over an hour later. That's an ingenious suggestion that provides a huge plus. Thanks!!!





On my tent neither the front door panel or the floor are sealed at all. The air will exchange pretty often through convection alone.



By comparison my tent is pretty small inside. About 80 cubic feet.

BHZ is can explain this better than I, but here's the theory I'm working with:

The candles produce radiant heat and the tent material is designed to reflect that radiant heat back inside the tent. Radiant heat works good for warming "stuff", like sleeping bags and people and rocks, but it doesn't warm air very well at all. So, in theory, my bag will be about the only "stuff" inside my tent to absorb that heat and should be warmer than the inside of the tent because everything else reflects the heat and air doesn't have much in it to absorb the heat.

Heating the rocks with the candles stores the radiant heat. Once the rocks are heated they start transferring their heat by radiating it to any stuff around that's cooler than they are. Hopefully lots of their heat will make it into me and my sleeping bag long after the candles are extinguished.

Here's a photo of the tent. It's simply made with SOL emergency blankets with the reflective surface towards the inside of the tent.

I'll let you know if it works as soon as I can...

Okay, I got to test it for one hour.

When I started the temp of the thermometer sitting on the top of the sleeping bag was 39º

I lit 6 candles and left them uncovered for 15 minutes and the temp reading was 44º.

At 30 minutes it was 48º. At that point I put rocks over the candles and the thermometer in between the bag and the neoair pad.

At 45 minutes the temp was 50º in between the bag and pad and the tops of the rocks were still cool.

At 1 hour the temp was still 50º and the tops of the rocks were just warm, but not hot. At that point I snuffed the candles and set the thermometer outside for 5 minutes after which it read 35º.

The short of it is, it worked pretty good. I need to test it out with just the candles for one hour, and just the rocks for one hour, and then see how long the heat from the rocks keeps the bag warmer.

I'll post some photos of how I set it up tomorrow.

Looks good.

I am surprised you went with a loaf pan. An esbit stove or cup wouldn't be able to hold as many candles but would be lighter and more compact. It would be interesting if you could weigh the candles before and after, so you could get an estimate of how much heat you are releasing.

I think you have the theory down pretty well. To add to what you said: The candle produces mostly radiant heat which is being emitted around the tent. It will heat up surfaces in proportion to how much area is exposed to the candle flame. That means some would be absorbed by the sleeping bag but quite a bit would be absorbed by the walls of the tent. Since the tent walls are so thin, much of that heat will be lost to the outside. By using the shields and rocks, you are absorbing most of the radiant heat and storing it at a lower temperature. The lower temperature means considerably less will be transmitted radiantly. Since the energy is not being radiated away it will warm the air around it and more will be contained within the tent.

Great explanation! Thanks!

I didn't use the steel bread pans for my tent test. I used small disposable aluminum pans and doubled them up and tweaked them so there was some air space between the bottoms to keep them from melting the tent floor, which seemed to work.



The foil pans are pretty light, and I think they have potential to be configured in a manner that will warm the tent better than I did in the first test.

With the pan open at the top as shown the heat just flies straight up to the ceiling. When the rocks were over the candles they sucked up almost all of the heat.

So, next I'm going to try putting a pan that's turned upside down on top of the one with the candles in it. I'll put a few holes in the sides of the lower pan to let air in, and some bigger holes in the sides of the upper pan that face the inside of the tent. I'm hoping that this will help disperse the heat more in the lower part of the tent.

I'll keep playing with the foil pans for a bit because they're cheap and available. I bought both them and the candles at the "Dollar General" and I'd like to be sure others can try whatever I use.

Here's the tent set up for the test:


Even when the rocks were over the candles I could feel the heat radiating off the ceiling onto the back of my hand when I held it about a half inch away. That being the case, it makes sense that lowering ceiling closer to the sleeping bag would warm the bag better. So, I might try suspending a sheet of the reflective material over the sleeping bag while the heaters are running too.

Here's the tent with the awning pinned down to help keep the heat inside:

Okay, I have a little update...

The Tent...

I decided to leave my tent set up after my last post. We had some rough weather coming and I wanted to know how it would hold up. Just a day after that last post we had sustained winds in the 20+ mph range with gusts up to 35 mph. Then it started raining. It rained good and long and hard for a couple days a few times and the wind blew pretty good most the entire time.

I checked the tent twice before taking it down. Both times it was still standing good and tight and almost completely dry. There was some stress on one upper corner where I've done some repairs with tape before, but that was it. There were a few teaspoons or less of water on the floor near one front corner after some pretty good downpours but that was it. My sleeping bag would have stayed bone dry through all of it.

I have to say that I was kind of surprised that the tent wasn't torn to shreds because the wind was howling for days up here on the ridge above it. That's pretty impressive in my book. Though the tent's not near ready for a thru-hike on the AT the concept shows promise.

Now, back to the heater...

It was about 35º and still breezy when I went back down there to pack up the tent. Before I took it down I lit six candles and arranged them in the two little foil bread pans (three candles each) like I mentioned I would try in my last post. That worked pretty good. The tent warmed up some while I was outside it for just a few minutes. When I got in it I could sure feel the difference. My hands were really cold so I held them over the heaters and, my gosh, that really felt good. That alone was a real luxury.

I checked and arranged the door panel so that it had some ventilation and put the heaters in the back of the tent and sat inside it for a few minutes. It was really pretty cozy compared to outside. I wanted to stay longer to see if it'd get warmer but I had to get back to my chores. The sun was setting and I could hear my burros braying for their dinner, and with their big ears they could hear me down there playing around, so I was totally guilt tripped into leaving.

Comments on the overall concept...

While this may seem silly to some these kinds of projects sometimes lead to commercial products that do work well. I'm sure there are others who are playing with these concepts. Using these heat reflective materials in clothing is getting a lot of focus and development dollars right now. Tents cannot be far behind.

It's important to consider that I'm using the proverbial "Spit and chewing gum" approach on this. When industrial design and manufacturing techniques are applied to any concept it changes the aesthetics and generally little else conceptually. My tent is just a prototype made to demonstrate the concept of how we can make a warm and light tent using these reflective materials. The aesthetics, or art and beauty of design, is not the focus of this prototype. That comes later, after the concept has proven merit. As it stands, this concept could be applied to most any tent design.

Where it stands...

There are some obvious improvements that can be made to what I've done so far. Among is to lower the ceiling. This would keep the warmest air closer to your sleeping bag and there'd be less air to warm. This would work better for retaining even your body heat inside the tent. I can hack my tent to test that.

As far as adding a heater goes, supplying air for the candles to burn from outside the tent would probably help a lot. My tent isn't designed specifically for that but I can hack it easy enough to test it too, and I will. At this point I'll keep hacking that tent to the point of diminishing returns and then make a new one based on what I've learned.

Current summation...

I have to say (again), there is not a tent made right now that I would use here in the Ozarks instead of this one. Based on what I've learned I'll be very surprised if we don't see some new tents soon that use a plastic material similar to this. It's cuban fiber light, durable, waterproof, warm, and inexpensive. I think it's got to happen and we'll all benefit when it does.

Tent heaters may remain something for the more adventurous DIY backpacker, though I can see how they might become more popular too if one can be made that works well for our purpose. This is a gray area right now that crosses over between bush crafting and backpacking, but it's an important area to keep pushing the boundaries on. That aspect of this project sits between those lines.

Really though, it's all just for fun. If you haven't played with the concept yet I urge you again to try it. At the very least it's an excuse to get out for a day and you might find you'd like to try it for an overnighter too. I think if a few more of us here were playing with this concept we could come up with something pretty nice.

Back in Boy Scouts (about 45 years ago), we used a soup can with tightly rolled corrugated cardboard up to about 2/3rds the depth of the can, with melted Gulfwax up to about 1/2" from the top of the cardboard. A blue flame would hover down in the can all night long keeping the tents toasty. It was much safer than candles, can't say about the carbon-monoxide, anyway, nobody died from it. ;-) The flame was the diameter of the can which put out substantial heat. I've not messed with one since but it did work well back then.

I use an e-blanket on the floor of my tent and use 2 candle lanterns hung off a line on carabiners with a foil reflector above them. Been doing this same routine for about 35 years. When its below 10 degrees (10 below is about max for me these days) it allows you to read and be relatively comfortable. They only burn for 2-3 hrs. at most before I want them out to sleep.
The concept of a heated tent is very intriguing, thanks for the posts. My wife would love it!

Well that is really interesting. I haven't given the candle end much thought except to note that the tea candles have a very light container for the wax. They have some down sides though too.

Custom candles built for the purpose have a lot of potential. The cardboard wick is sure clever. I'm going to have to play with that.

Thank you for sharing. That's the kind of info I'm needing to build on this.

We've got some perfect weather here right now to be experimenting with this. Unfortunately we have a big shindig for Thanksgiving and I'm under orders to get things ready. I still get to play with fire though, I'm smoking some turkey and ham with some hickory, so I'm still having fun!

No kidding. That's really encouraging. I've just started playing with the tent heater concept. I made my tent primarily to use with a campfire but the prodding to try out some kind of heater came when so many here said they don't like or can't have campfires. So that presents another problem to solve and I'd heard about backpackers using candles to heat tents. Plus, even I can't always have a campfire so I just had to start playing with it.

I've been looking at some candle lanterns. The foil pans I'm using work good, but they might not pack so good. They're easily crushed. It's also pretty easy to reshape them, but that could add a fuss factor that's not worth it.

The e-blanket floor really helps a lot to keep the ground from sucking all the heat out of you. I really like the bubble foil floor in my tent. It's easy to clean and durable, and it's replaceable. I haven't had to replace mine yet and it's still in very good shape. That's some pretty amazing stuff.



Heck yeah! A small campfire can be pretty darn romantic. Add a warm and cozy tent made to go with it in the mix and if I'm cooking dinner my wife is there!

Bill, are you using Reflectix? I use it for specific insulating projects and radiant heat in construction. I've never tried it DUH!!!!!!! thinking it would not stand up to being rolled on as a floor. If it works for you, I'll have to get a piece and roll it up and attach it to the outside of my pack. I know my circulation is on the downhill slide as I get older. Making shelters with some warmth in them is very encouraging to keep doing the things you love. Cool post.

Yep. That stuff is amazing. My neighbor and I started using a small piece for butt warmers a few years ago and we've been playing with it ever since. My tent floor is 40"x80" and rolls up to a 5" diameter x 20" long roll. I still carry a piece for sitting on too. It's about 16"x40" and I fold it into a 8"x10" square about 3/4" thick. I even keep a piece in my car to sit on this time of year.

The next few days will be a good opportunity to test the tent heaters. We've got rain, sleet, freezing rain, and snow in the forecast with Friday's high expected to be around 25º and a low the next morning around 7º.

Thanks for the reply, Bill. I have to buy some to insulate a doorway we don't use, so I'll get some extra. I'll do some experimenting and report back.

This video (fireplace in a floorless shelter) is a bit crude--but interesting :

http://www.youtube.com/watch?v=4DNCFa428Ho

With a few tweaks (better & taller chimney) and extreme caution it could be pretty nifty.

He must hike where there is no wind and has plenty of deep, moist dirt. Complete opposite around these parts.

Frozen ground, snow and wind, pretty much kill the concept for me.

The problem with that type of fireplace is that it draws cold air into the tent to supply the air for the fire. That keeps the smoke out, but makes for a very drafty room. I don't think you'd really warm that tent much with that set up, but I'm sure you could feel some heat coming from it.

I never seen a poncho rigged like that though, that's pretty cool. I think a tent like that made with the SOL emergency blanket material and a bubble foil floor would be a pretty good UL set-up for those into minimalist backpacking and could work great with a candle heater.

If the goal is car camping, then maybe changing the paradigm would help.I have a heated jacket liner and gloves for my motorcycle.I've ridden comfortably for hours down to 15 degrees. On one maxi-scooter (Yamaha Majesty 400) I wasn't certain the battery would handle the load, so I got a marine battery to put under the seat.It would last for over 12 hours at the highest heat setting.

There are electric car blankets on Amazon for about $24. There are also small electric heaters. These would most likely last a night if powered by a marine battery.

I'd be afraid of any flame in the tank giving off carbon monoxide which can cause severe headaches or death.

That's really not hard to prevent. The easiest way is to blow out the flame.

Honestly, you couldn't burn enough candles inside the tent I have now to suffocate yourself. The front panel doesn't seal at all on the sides or floor so the air is constantly exchanging, hot air rising and pressurizing the air space near the ceiling of the tent where it escapes through the upper ends of the front panel and cold air rushing in below to replace it. Just your body heat causes that to happen.

Of course, the cold air is heavier and wants to stay near the floor so this creates the age old problem of your sleeping bag being on the floor of the tent where all the cold air is. That's the problem I'm attempting to deal with. I want to warm that air up down by the floor.

Another approach is to move the sleeping bag up where the warmer air is. A simple tarp over a hammock will work better with the heaters I'm playing with but I think controlling the way air flows can offer improvements to heating a tent with candles and I want to play with that some more yet.

I did a YouTube search for "Super Shelter" and "Bakers Tent" a few days ago to see what's new there. There are some cool new videos. There's one where a guy running a "Survival Skills" type course had a bunch of people out on a cold night who built Super Shelters and spent the night in them.

These videos get a lot of views but most all the videos rig up a "Super Shelter" in a "survival" situation, which I find a bit curious. I mean, this technique is now several years old and if you've already thought ahead enough to buy "Emergency Blankets" and visqueen to make a "Super Shelter" why not just make a lightweight tent like mine? Why wait?

It's a curious thing that others haven't done this already at this point because it's a very natural evolution of the concept, but overall the concept seems to be stalled with the "Survival" shelter. This is bugging me because there's a lot of room to move forward with it for backpacking and I'm basically lazy and know that if others were working on it I would benefit from their good ideas

Looks like the end of this week will get pretty cold. Highs in the mid 30ºs on Thursday and Friday. I think I might head out somewhere in the forest and make my own video and post it on YouTube. I'm hoping this will nudge others to start innovating on this concept. If it does, it will sure be fun to see what others come up with.

I set the tent up a few days ago to see how it'd hold up in a snowstorm. We got about 5 inches the night before last.

I wasn't able to get down to where it is today, but tomorrow the forecast high is only 8º with a wind chill values as low as -20º so I'm going to try and get to the tent tomorrow. Hopefully it's still standing, it's been pretty windy too so it this was a good test for it.

I'm going to bring some tea candle heaters with me to see what I can do with them. I'll also bring some fat pine to see if I can get a fire going. All my wood is under snow, and it rained before it started snowing, so it will be a challenge.

Or I might just sit inside all day and watch TV