Candle heating a van... Check my math?

[One Awesome Inch]

I was curious about how many candles it would take to keep a van warm. So I did some calculations.

Three things to keep in mind when considering this info:

1. I did not include any data of heat loss due to windows/ventilation utilized
2. If I were to do this I would warm up the van to room temp (21 Celsius) using a propane heater / Mr. Heater Buddy, before relying on candles to *keep* the van warm as I believe it would take the candles quite a while (hours?)to get the van warm without help from another heat source.
3. I am also not taking the insulation factor into account

A few notes...

I'm mostly doing this in metric since I am Canadian and thats what I know best. However its a mixed bag since some of the measurements are in feet. Hey, watchya gonna do?

These calculations are applied to a typical sized standard van which I believe the interior "living" area to be roughly 10ft Long x 6ft Wide x 4.5ft High. Like I said "roughly".

You can calculate the amount of BTUs required by using the following method:Measure the space’s dimension to determine cubic feet. (Length x Width x Height = Cubic Feet). Subtract the outside temp from the desired inside temp to determine the temperature increase. If you have measured temperature in CELSIUS, calculate the required BTUs with this formula: (Cubic Feet x Temperature Increase x .2394 = Required BTUs)

To calculate BTUs required---> 10Lx6Wx4.5H = 270 cubic feet of interior space in the van.

270 x15 x 0.2394 = 970 BTUs needed to keep the van at 20 celsius if its 5 celsius outside (20C desired temp subtract 5C estimated outside temp).

158 btu per candle hour --> 970/158 = 6.14 candles

Thus, it would take a smidge more than 6 candles to keep the van at 20C if the outside temp was 5C..... Right???

As stated this does not calculate for van insulation, ventilation etc. Just rough estimate type calculations here.

Anyway, I've quite likely made some mistakes in all this so please let me know what they may be.
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BTW, the Micro (smallest) sized mr. Heater Buddy puts out a max of 3800 BTU per hour. If you are heating an area 270 cubic feet (requiring 970 BTU per hour) that micro mr. Heater Buddy should be able easily do the job... as long as the temps dont get crazy cold.

 

[akrvbob]

Do all candles put out the same amount of BTUs? I guess they all have basically the same wick and the variable in size is the amount of wax which makes them bigger or smaller but wouldn't affect BTUs, just how long they burn.

Bob

 

[One Awesome Inch]

Thats a good question... and good answer!

I got my 158 btu per candle based on this:

VAC engineer here with a mechanical engineering PE. A quick calculation to show your candle theory. Im going to use english units, since thats what all my ASHRAE tables are in.

120 m3 = 4230 ft3 for my calc. This gives you about 420 square ft with a 10ft ceiling. To make it really easy, we can make it a 20x20 room.

All of heat used for the calculation is sensible heat since we dont figure into account heat loads caused by equipment/people etc when doing loading calcs for heating.

Depending on where you're located due to temperature is going to make a difference on loading. But I'll assume you start at 70 inside and 40 outside, because I don't have your temperature data offhand. We also calculate heat load at night (when its coldest), so solar gains are neglected.

Heat loss through your walls (transmission) will be calculated by Q(sensible heat)=UA(Delta T) where u is the inverse of the R value of your insulation. Assuming R-19 and a ceiling height of 10ft gives you: Q=800sqft(.05)(30)=12000 btu/hour.

Parrafin contains 49KJ/g of energy and 17 g of parrafin per candle so you get 833KJ of energy. Averaged over 5 hours thats 166.6KJ/candle-hour

Using the conversion 1KJ=.947 Btu that will give us 157.7 btu/candle-hour.

12000/157.7=76.09 Candle hours

So you will need quite a few candles burning to heat up your room.

Note this is a pretty basic calculation, but it does the job to show the principle [/

quote]

(From this url: )

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I should mention that naturally those numbers are much bigger because those calculations are used to heat a room much bigger than a van interior.

 

[Luisafernandes]

The question is; would you want to be breathing in all that wax? In the past while having a small scented candle burning in the room I've had pain in my chest, like there's some kind of weight on it or something every time I take a breath.

 

[SoulRaven]

No need to buy candles just leave the little buddy heater on pilot light.

The Little buddy heater heats a 240 square feet travel trailer on low 4kBTU.

 

[Stargazer]

I don't know about the math, candle ingredients or btu's, and all that jazz. Here is what I do know.

I have a conversion van with the standard interior walls and ceiling -- 1/4" plywood covered with automotive upholstery fabric. NO insulation. Windows have several layers of stuff that keep out cold and heat, up to a point.

I have and use a lantern called the Candlelier, with three candles that will burn up to about eight hours. You *could* heat water over it, if you are very patient. It will take the chill off if outside temps are at or above high 50's and you are sitting right next to it. In colder temps, I will preheat with the Mr Heater Buddy and use the candles to maintain but it doesn't last much longer than no candles, maybe a few more minutes?

On the plus side, I love the ambient light of candles (unscented) and there is a psychological factor of watching the dancing flames when it's too wet or dark or whatever to be outdoors.

If one relies on candles for heat, better have LOTS of them and be prepared to be cold.

 

[akrvbob]

I know people who try to heat with candles and it usually doesn't work out well.

The people I know who use candles only use one and they start with a cold van and it doesn't work But I'm more impressed with your idea than any others because you set realistic goals using realistic means.

First, you use a Buddy heater to get it very warm. I've done that many times but the van soon gets too hot so I turn it off. Then it gets cold and I turn it back on and then it's too hot--repeat over and over again. I hate that so I stopped using it. So now all you have to do is maintain heat or even allow it to slowly cool off.

Second you don't use one candle, you use 6, that just makes a lot more sense to me!

I can see it working!

My friends usually bought one of these Kandle Heaters and were dissapointed:
http://www.heatstick.com/

But using your idea with 6 candles I think it could work. Those things are expensive but you can make one for much less.

One of their big advantages is they absorb a lot of the moisture from the candle and the soot stays on the pot.

But then you have the safety risk of 6 candles burning. Open flame in a van is always scary!
Bob

 

[MK7]

Candles in glass containers sometimes explode. Look it up, especially when it happened to Ozzy Osbourne's wife. Wax will be everywhere to clean up but that's not as bad as burning wax, setting your van on fire while you're sleeping.

 

[LeeRevell]

How about trying the idea (plenty of Youtube videos) of the candle heating using an inverted clay pot over them? Makes more of a 'radiant' heater, possibly a bit more efficient? And keep a fire extinguisher handy......

 

[MK7]

How about trying the idea (plenty of Youtube videos) of the candle heating using an inverted clay pot over them? Makes more of a 'radiant' heater, possibly a bit more efficient? And keep a fire extinguisher handy......

Try it. It won't work too well when it's cold out, even with 5 candles going. And now you've got 5 separate flames burning inside your van. And candle don't last very long, even the ones that says "Survival Candles". The ones that lasts long and cheap, are the $1 Jesus candles in a glass, cylindrical jar. I had one going for over 8 hours and it didn't even lose 1/4 of its wax & wick yet....but then I read about how they can literally explode, sending hot burning wax all over the place.

 

[One Awesome Inch]

I would like to add a couple of caveats.

First of all, I would not use regular candles. Regular candles are a petroleum by-product, bleached white. There is alot of toxins in there I would not want to be breathing in on a regular basis. I would use a veggie oil based system. Apparently Virgin Olive Oil burns very cleanly. However, I would like to know if its completely free of toxins... or almost. Anyone know?

I know that the Buddy Heaters are quite safe when used properly with the required ventilation. However, being from a very humid climate, the PNW where its usually 85% or more humidity, I dont want to use propane all the time as it would just increase, humidity which leads to condensation which could lead to mold. I am pretty sure veggie oil "candles" burn alot drier and cleaner. I have also read about some van dwellers claiming that kerosene is much better than propane as its a drier heat, BUT kerosene heat also gives off alot more toxins than propane from what I have read. If it was once in a blue moon, I'd try it, but not on a regular basis. Cancer is a major bummer... to say the least.

The other thing is that I would use 8 wicks in two groups of four. Each group of four under its own clay pot. I am not 100% convinced of the astonishing claims of clay pot heating, but I would bet its better than without it, for the fact that the heat doesnt go straight to the roof. If its radiant and the pots absorb moisture... all the better. Naturally ventilation is absolutely essential and I think pre-heating to get the van nice and warm is an important step to ensure that this method of heating your van is actually going to work effectively.

Naturally, I would take every precaution with open flames and make sure they are extinguished before going to sleep etc.

 

[MK7]

Dude, just try it out. Go to the $1 store and buy a pack of candles and a clay pot. Burn 8 of them and see that it's hardly any heat at all. That's only $2 for this proof.

Yes, these are those little round, shallow candles that won't burn too long for $1...but I'm just trying to show you that they won't give off much heat at all, especially when it's freezing outside. I tried it without opening any windows because it was just so cold outside. You can burn a can of Crisco by putting a wick in it. There are YouTube videos on this. But not much heat. Not worth risking that my van catches on fire with 8 candles burning.

People on here warned me about spilling kerosene and not to use liquid fuel in a van/home...I thought they were absurd..... until I spilled some kerosene and it's all soaked into my carpet.

 

[Willy]

Years ago, I had a very well insulated camperette that I took down south to AZ. Went visiting up in Springerville, around X-mas, and heated that unit most comfortably with a kerosene lantern with the wind a'howling and the temps considerably below freezing. ..Willy.

 

[highdesertranger]

first off any open flame no matter what fuel you use is going to produce toxins. no way around that one. that really doesn't bother me but it might bother other people. from what I have read on a quick search on average you can expect about 50btu/hr from a candle. so even times ten that's only 500btu's. that's not going to keep up with the heat loss in a van. as others have said then you have all those separate flames burning. I think you would be miles ahead if when the buddy was burning you put a metal water jug(not sealed) if front of it and heat the water. then when you turn the heater off the jug would radiate heat for quite awhile. much safer than candles imho. highdesertranger

 

[cinemaphonic]

No need to buy candles just leave the little buddy heater on pilot light.

The Little buddy heater heats a 240 square feet travel trailer on low 4kBTU.

Does this work? leaving the pilot light on to warm the van? That must extend the life of those 1lb canisters by a lot.

 

[MK7]

Does this work? leaving the pilot light on to warm the van? That must extend the life of those 1lb canisters by a lot.

There's a guy who posted a YouTube video about running his Buddy Heater on pilot or a little higher, by fidgeting with the knobs. He says it works and runs 10+ hours as I recall. The MFG says to not do this though.

 

[surfer]

Here is what I've seen on the subject
Cost per Therm:

 

[ccbreder]

Can't get this horse to stand up. Keep beating. If you heat your space with candles or pilot flame, you will be very uncomfortable.

 

[Mac J]

Here is what I've  seen on the subject
Cost per Therm:

I just watched the short video you posted. 
Sure, this guy gave up his money. He now spends other people's money. That's the same economics our kids use when they move back home 'to save money'. They spend ours.

 

[GotSmart]

Using my little buddy on pilot, I was able to keep warm enough to sleep. Of course I had heated up the van first.

One bottle of fuel lasted me for 2 1/2 days.

It worked for me...