The Amazing 1 Candle Space Heater

[Steadfast]

The 1 Candle Space Heater
 

I just researched and built two 1 candle powered space heaters!
They provide light and get up to 230 degree temperatures from the energy released by a single candle!
They cost around $15 -$20 to build one!



Tools needed:
Tin snips and small pliers

Parts:
3 small THIN Terra Cotta Pots.  (get at Michaels not at Lowes)
1 Terra Cotta Pot base. (get at Michaels not at Lowes)
1 carriage bolt.  (1/2 inch longer than biggest pot)
A bunch of nuts and washers of various widths
1 star shaped cookie cutter.
1 Glass jar/vase to hold candle

 This is the smaller, MOST efficient , heater of the two.


This is what is going on inside the pots… The washers act as heat diffusers…
So, you want some WIDE washers too, which don't touch the edge of the pots…
(Run with this idea, but don't get all obsessed about the details here.)


The middle pot needs to be suspended upon a “breathing bracket” so that the Candle will have air.
This, my Modified breathing bracket, is made out of a star shaped cookie cutter...
Use tin snips to clip edges of star and fold them out to fit the top of your jar/vase.



This is my 1st Bigger Pot experiment. It works but not as well as the smaller model.
The “standard hardware store plant pots” are heavier, thicker  and take MUCH longer to heat up!

[Bruce S]

Steadfast;
Here's another post that great minds think alike!  .
Nice !!   
It's the thermal mass that makes these so nice.
I'm doing something similar,  however I went the thicker terracotta pots, recovered them from old Rosemary plants, so no costs.
We also like them big enough to sit on, once the flame is out; as they will hold the heat a few more hours.

I'm also using some of my really nasty oil left over from Bio-D, and since it burns much slower than paraffin based candles I use two of them.
On the very top where I add a separate pot; I put a tin can of water to add moister to the space as well.
Thanks for the post!
Bruce S

[SparWeb]

I don't get it.  Candles are nice to look at - why cover them?
Wouldn't all of the heat from the candle be released into the room anyway?

...granted there is the nice aesthetic warmth of the pot, of course. 
I could warm my hands on it when coming in from outside in this -33C night!

[Frank S]

Sparweb placing the pottery over the candle prevents the heat from simply dissipating. It does not cause the candle to produce more heat as some web sites might try to make one believe, but having the heat retained in the clay pot is similar to heating rocks in a fireplace then taking them somewhere else for the radiant warmth
 I used to make alcohol toilet paper heaters in a 1 lb coffee can and place a 8" clay pot over them to heat a tent with. And used 3 or4 fondue candles in a tin cans with a clay pots over them to keep warm in the cab of a truck many times
 not a lot of BTUs but sometimes just a little warmth is enough to keep from having to idle the engine all night 

[Bruce S]

Frank S
Perfect analogy! This won't by any means keep much more than a 10x19 foot room above freezing , but when ya sit on it the radiant heat sure runs the chills right out.
Since we have about 300 of those tea candles , it's a nice way to use them up.
4 of them under a 12D x 12H inch clay pot will certainly keep the coffee cup warm.
and YUP! come in from shoveling ice off the side walk and it sure is nice  .
I have a pizza stone on the floor then a cookies cooling rack above that and it gives a nice glow, with the added security that our hound/Shepard mix "puppy" won't try to eat the wax candles
I'll try and remember to get a pic up here tonight or tomorrow.

[niall2]

this candle idea did go viral on the web a while back  ...."money to saved".... dont get me wrong , i do like candles 

so ....at the end of the day the heat energy (lets say watt hours worth)  is exactly the same as a naked candles wax content  .....?

or is it like the viral stuff protents  ?

     

[Frank S]

this candle idea did go viral on the web a while back  ....and dont get me wrong , i do like candles 

so ....at the end of the day the heat energy (lets say watt hours worth)  is exactly the same as a naked candle.....?   

 that is true however the clay pots serve to keep it concentrated where we want it instead of just rising to the ceiling with the smoke of the flame 

[niall2]

whats wrong with a well insulated celing ? .....how do concentrate heat , or cold for that matter .....one tends to go up , the other  down ...

no magic methinks 

[birdhouse]

i like this idea as much as i don't.  a candle will only put out so much heat even if you use some NASA based technology with it. 

for those warming hands, coffee, or bottoms (sitting one one) it sounds great.  using the heat directly into your body.  but as far as heating a room? 

my wood stove is currently broken, and i don't have a furnace.  so i've been running two electric space heaters.  with this cold snap, i have yet to get the house above 62.  i pulled out a bag of those little tin candles and lit 30 of them.  i got the temp in my living room to  rise to 63. 

some may say, the heat just rises to the ceiling...  isn't that true of all other heating methods aside from radiant?  or convection (hands/bottom on the pot). 

i'd say this is a decent idea, but not near as AMAZING as all the youtube videos make it sounds. 

adam

[niall2]

just got the first small wood stove installed here too......realization now is .....i need a "lot" of wood ........i like the tea tree candle idea though .....but space heater ....not so sure 

[SparWeb]

Had a bit of time to think about this (of course I'd be the one to over-think this sort of thing).

I really should have realized what's happening in this little system that makes it effective.  At first I was thinking only about the light being radiated - converting visible light into heat is rather pointless because the visible light is about 0.01% of the energy being created by the flame.

Then I realized that there is a heat-transfer process going on that is doing more than just absorb heat and radiate it all back out.  The important feature is the temperature at which it is radiated on the surface of the pot.  The temperature of the candle (about 1000F) creates a heat whose radiation is mostly in the near infrared part of the spectrum.  Because air is transparent to the near infrared, the energy can radiate far away.  If the candle is in a room, the energy radiates out to the walls and is absorbed there.  This is why Birdhouse wasn't satisfied with his candles.

When the candle is covered by a clay pot, then all of the near-infrared heat is absorbed by the clay pot.  It heats up, but not as hot as the flame.  It will radiate its heat out in the far infrared, and that energy of "light" has a much longer wavelength.  This energy does get absorbed by the air of the room, because the atmosphere is not transparent to far infrared light (ever hear of the greenhouse effect?) so the air around the clay pot is readily warmed by the temperature of the pot.  The large surface area of the pot works both ways to distribute the heat to a larger amount of air, as well as reduce the temperature of the flame to a lower temperature (200F) that radiates better in the far infrared, which is absorbed by the air in the room rather than escape it.

This is also the reason why a brick/stone/masonry fireplace is used to contain and re-radiate heat into our houses, and why it's been so satisfactory for centuries.  So of course I'm just describing in scientific mumbo-jumbo what was always obvious to our ancestors.   

[birdhouse]

If the candle is in a room, the energy radiates out to the walls and is absorbed there.

i don't know if i fully agree with this.  i lit another 30 candles as the first set went out, and they have still been giving me 1 deg F boost even as evening is approaching and we're supposed to hit 14 deg F tonight for the low. 

so i did a very sloppy non-scientific test.  the candles are all located on a short metal filing cabinet (safe).  the cabinet is near a corner, with two interior walls creating the corner.  when i hold my hand on either of the interior walls, i feel no noticeable difference between the temp on the same interior wall on the other end of the room, yet when i hold my hand directly above the candles, i notice a HUGE difference in temp.  i believe the candles are heating the air directly above them, much more than the walls. 

This is also the reason why a brick/stone/masonry fireplace is used to contain and re-radiate heat into our houses

now your mixing in convection via thermal mass into the equation when the first portion of the post was about radiant heat. 

a candle can only produce so much heat.  the pot does store thermal mass, but also takes longer before heat is felt upon lighting candles.  the same heat is released, just slower, yet longer with the pot.  i do believe there is some radiant heat released from a candle, but thinking it is a very small percentage. 

i do think the pot idea is very keen for direct convection use.  IE: sitting on (big pot), warming coffe and or hands. 

adam

[Bruce S]

As I continue to use mine, let's see if I can help a little further.
Yes the big clay pot gets heated slower than if you just lit the candles and let them heat the air on it's way up to the ceiling. I have tall 10foot ceilings, that's a little high for me to get up to :-).
The pot(s) get warmed, I use 4 tea candles at a time know as it's 11F !! here  .
The pot(s) stay nice and warm, this warms the air in what I believe a more evenly distributed fashion.
It is also nearer to me rather than to top of the ceiling, and when coming in from scraping ice/snow off my panels I can pretty much put my hands on them pot(s) and warm them.
To me this is very similar to the Russian style thermal mass stoves, Mother Earth wrote and explained about 2 decades ago.
I am using a mixture of pots to see where the sweet spot is ( I have all winter to play  ). It also seems the metal from the bolts work to help direct the heat to the pots , but I had problems keeping the candles lit unless I dropped to fewer candles ( no air). The closed off top area is done so by my coffee cup or water jar (moister into the room) . plus is keeps the smoke off the ceiling meaning one less thing to clean later.
NOTE:
Those who want to try this REMEMBER there is no free lunch, you can create enough carbon monoxide in a closed off room to be hazardous !!
Plus this is no where near efficient heating of a room. I have waste Bio-D therefore I can also use it with wicks, but it too, is a dirty smoke and much better and SAFER! mixed with sawdust and burned in my double walled stainless steel lined chimney.
This could be a life saver in the even of an ice storm and the power is totally out, but that's about it.
It is pretty, and smells great!! when cinnamon scented candles are in the mix.
The pots once warmed will continue to be warm for a short period of time depending on the air movement in the room.

If you are like Fab and I , and have left over Bio-D that's not any good for the engines, this would be a good way to make use of it, if you don't have access to sawdust and a fireplace.
There's a few U-tube vids that are total BS, in they don't really know whats what and merely do the short test, one test on there try it in a room full of tile, and said it didn't work (well DUH!) , he had a lavatory with a porcelain mass, walls with tile and no less than 3.8L of water to overcome thermal temps. 
Truths I have found= the pots get hot! , it does work( but only just barely). Not efficient. Good hand, coffee/ tea/ water warmer. MY Cats don't like it.
   
Hope this helps
Bruce S

[niall2]

 ....i guess i,ll have to build one Steadfast and see how it works out .....

i got curious about the amount of heat energy (btu ?) a tea light puts out , mainly because i bubble wrapped some old single glaze windows to try to stop them being so completely awful at insulation  .....

i seen somewhere (not sure , probably utube , iffy ...) that a typical tea candle light is about 30 watt hrs energy ...a car tail light on for 2 hours ?



 

[dnix71]

Tea candles/lights get their name from their original use.
http://en.wikipedia.org/wiki/Tealight

A very small flame can be used to heat water. No electricity = no problem making tea or coffee, or warming a cup of soup.

It doesn't take much rendered animal fat to make a tea candle. Kerosene is a modern fuel and kerosene lamps are expensive for the poor to operate and a fire hazard.

Using a candle for just light is less efficient than light + capturing the heat for cooking.

A tea candle isn't going to warm the room, though.

I keep a bag of tea candles stored in the fridge in case all power is lost for some reason. After hurricane Wilma I burned a single candle hanging from the ceiling to light my room enough to safely occupy it. Just enough light to see, not enough flame to be a fire hazard or asphyxiate myself.

[DamonHD]

A normal candle puts out about as much heat as a human body, ie about 100W.

But a candle is a very very inefficient way to produce light in return for (say) carbon or cost per lm over time compared to (say) LEDs.

Rgds

Damon

[Bruce S]

This has turned into quite the post .  .
For those thinking of using the candles for light, "don't". yup they are pretty and yup they will light the room.
BUT, there are a few things that go into consideration.
1) Danger, open flame type danger.
Here is St Louis there are have already been 3 house fires from the resistive type electric  room heaters, an open flame is a problem waiting to happen.
Take a look at some of the posts Rich and I put up in 2010 during our trip to the Philippines, the carbon build up is an eye opener, then think of it being in your lungs.

2) These should be thought of as emergency only.
I tested mine using the good ole stand by, paraffin candles, then went to carbon neutral soy & beeswax, which actually work better and smell better.
Still this should be used as emergency heating not lighting, think heat with a little bit of mood lighting.
IF you have long term heat needs and have "room solid" fats available, try those instead of paraffin based candles. AND save the paraffin for sealing jellies  .
One that I will be trying is some coconut oil that is solid at 75F , plus beef fat from left over trimmings ( better to make a possible candle than eat the extra fat IMO ).

MOST important safety , safety safety!!
Cheers
Bruce S
For those looking at the electric bill go with LED bulbs as you can afford them. My cost analysis show mine will pay for themselves (buying 60 watt eq at $11/ea ) in 6 months, then realized savings for the next 5 or so years.
Going with CFLs is good too, but I like LEDs