Emergency Candle Heater: Building a Single Candle Clay Pot Radiator

With cold weather fast approaching, I wanted to share a cool little project that I did over the weekend that can provide some extra heat during a grid-down emergency situation. With the heat from a single candle, it is possible to heat a small area during an emergency ­– if you can capture that heat.

Step One: Build a Small Emergency Shelter inside your home.

If you live in an apartment, or a house that doesn’t have a fireplace or wood burning stove, winter power outages can quickly turn into life-threatening emergencies. When the temperatures start to plummet, you need to take action.

The first step you should take is to build an emergency shelter, or warm room, within your home. It’s a lot easier to heat a small walk-in closet or pantry than it is to heat an entire home. So the first thing you want to do is find a small room or closet, and then start insulating.

  • Line the walls with couch cushions, blankets, or anything else you can find that can trap heat inside the room. Think about when you were a child and built forts in your bedroom; we’re going for a similar concept here.
  • If you have an emergency reflective blanket, putting one up can help reflect heat back into the room.
  • Depending how many people are in the room, body heat alone can be enough to keep the room at a tolerable temperature.

Step Two: Build a Single Candle Emergency Heater

Once you have your shelter built, a single candle can be used to help heat the room. Building a small Clay Pot Radiator allows you to capture the heat generated from a candle, heat that is normally wasted, and slowly build it up inside a makeshift radiator.

The Single Candle Clay Pot Heater

Building the Clay Pot Candle Heater

The heater is actually pretty simple to make. One long bolt, a dozen washers or so, about 7-8 nuts, and a couple small terracotta pots is all you need.

Terracotta Pots

  • Place the Long Bolt through the Terracotta pot, separating each pot with a couple washers and a nut.
  • The Center bolt, washers, and nuts will all conduct the heat from the candle. The metal core will get extremely hot, trapping the heat and radiating it out to each clay pot.
  • The heat will slowly build up inside the pots, and then will begin radiating heat around the clay pots.

Inside the Clay Pot Radiator

I’ve seen this project on some other sites, where people suggest it can be used to heat a home for pennies a day; IT CANNOT!

This is in no way meant to heat a house or even a large room, but in an emergency situation, it’s a good way to capture heat from a candle and then radiate it out into a small area.

Candle Pot Heater

32 Comments

  1. marita
    November 12, 2014 at 12:26 pm

    Actually… I have been using a Terra cotta heater for two months. It’s at 32 degrees outside today. 72 degrees in my house. They are excellent space heaters. Oh and by the way my furnace isn’t on. With these space heaters I have no need currently for my gas furnace. Tea lights burn for 4.5 hours.

    • joe
      November 17, 2014 at 5:38 pm

      are you truly able to heat to use these as space heaters?? it sounds hard to believe, i would even be happy to use it as a supplemental heat to save some money on my natural gas bill.

      • Kathy Kelley
        November 30, 2014 at 6:34 pm

        No. It is NOT a form of alternative heat. It will not heat a room that is an
        8 X10 . It is more like a foot warmer, but the pots do put out respectable heat, just not much of it…..Prepping For Your Survival

    • jc
      November 28, 2014 at 9:17 pm

      I’m calling bullshit on that!

    • Enter your name...
      November 30, 2014 at 7:34 am

      You must have a LOT of these to keep a house warm. I built one and it will keep a 4’x4’x6′ area comfortable. So unless you live in a cardboardbox or have multiple heaters. I say bullshit!!

    • Joy
      August 4, 2016 at 1:29 am

      These terra cotta pot candle heaters work great. 2 Christmases ago we were without power. I built one of these with 3 pots, and 3 little candles in it nicely heated my large bedroom. It was around freezing outside and we “cricked” the window a little, and it still stayed warm. We were careful, when opening and shutting the bedroom door to do it quickly to keep the heat from escaping. We used 3 bricks in a u shape instead of rocks, just the right height to keep the candles burning. I made another similar thing from a glass bread pan and an overturned cooking pot, on top of it, candles inside the bread pan. I put a plate on top of that, and it heated half a can of corn at a time to eat.

  2. old soldier
    November 13, 2014 at 5:35 pm

    Great Idea!!! Intend to build one as soon as I can. Don’t have a fireplace and with the weather being what it has been and will be, I definitely need this just in case of power outage.

  3. William McCarty Jr
    November 13, 2014 at 7:20 pm

    I have a wood stove but, I think I will build one just to see how well it actually works. I can always use it for a backup if for some reason I run out of wood.

  4. November 15, 2014 at 10:50 am

    Wonderful idea. Going to try this soon.
    Thanks…

  5. Rob
    November 19, 2014 at 11:08 am

    This is nonsense. A candle only can produce roughly 250 BTU/hour. This insufficient to heat any space of any significance. Plus since its burning inside, it consumes oxygen and produces carbon monoxide as well as carbon dioxide. In a small space, this could be toxic.

    • Runner
      November 22, 2014 at 6:40 am

      People used to only have candles (or lamps) for light in their houses at night. I could be wrong, but I doubt that one or two candles could cause significant carbon dioxide/monoxide buildup in a typical room (even a small room). That’s got me curious how a candle’s CO2 output compares to a human’s. Anyway…

      As far as heating, I’ve given this a lot of thought. There are 2 important questions. 1) What is the most efficient way to disperse/retain the candle’s heat? 2) Is heat added faster than it is lost?

      I believe the answer to the first question in this context would be radiating the heat (like from the clay pots). It helps spread out the candle’s heat more evenly and avoids pooling it at the ceiling (like convection).

      As for the second question, that is greatly affected by the room’s insulation and size. You said that the heat is insufficient to heat any significant space, and I agree that as a room gets larger it becomes much more difficult to heat, but it comes down to insulation. If you could retain 100% of the candle’s energy, you could eventually heat any sized room until it was insufferably hot…also, assuming you had a forever-candle. So it’s a question of area and heat retention; not just size.

      Of course, if you are in a large room without good insulation this would likely not be an effective heater. But it would still be a good emergency heater for warming a few humans who huddle close to it. Much better than trying to warm yourselves up over a bare candle flame.

      • Judith
        December 24, 2014 at 5:10 am

        oil candles burn clean and they burn much hotter than wax candles.

        • Tina Riley
          April 21, 2015 at 2:17 pm

          I used the refillable candles from fire fly fuel. the flame stays at the same height as when you light it. Where wax candles slow go down.

    • Denise Maloy
      January 7, 2017 at 9:32 am

      I just checked out the c02 that candles put off,
      There was a post about being prepared for winter (January 6, 2017) things to keep in your car, I added a post about this clay pot heater and right away c02 was brought up. So I went to youtube.com and typed in c02 and candles. Sure enough burning too many candles can be dangerous, so people please be very careful when burning anything to keep warm in winter, not only does fire danger go up in homes in the winter, but now with this clay pot heater there is c02 danger.
      When I first saw the clay pot heater my thoughts were make several and or bigger as I live in a all electric home and there are times when power goes out. (Oregon Coast ) we are dealing with ice and snow right now.

  6. James
    November 23, 2014 at 2:03 am

    Hmmm I have to try this, but what if you used a different heat source, like a can of sterno for cooking, that’s meant to put out higher btus?

    • poacher
      November 30, 2014 at 7:25 pm

      I tried using a 3 wick citronella candle….huge mistake I sat the candle in a pot (really glad I did). At one point the top of the candle really want crazy…slid the pot out and put it out in the bath tub….been using one in my bedroom for 2 winters now… I it stays comfortable…I did put up 3 layer curtain on my windows in bedroom… did think of the space blanket…might get a couple to add to the curtains…IL continue to use it. Candle only….

  7. monica
    November 27, 2014 at 6:18 pm

    this does not work, i went out and bought all supplies as i have small room in my home and i wanted to test the theory…FORGET IT…SAVE THE $26.00

    • deez
      November 28, 2014 at 7:38 pm

      How the heck did you spend $26.00 on 3 clay pots, one bolt, some washers and a few nuts?
      Are you including cab fare in your cost estimate?

    • jc
      November 28, 2014 at 9:15 pm

      Your nuts if you spent $26!

  8. Mike Burke
    November 28, 2014 at 8:48 pm

    I’ve tried it and as you say, it ain’t impressive, but…I have this idea of closing in 3 sides of my circa 1960s small dining table with heavy cardboard and use the heater with 2 clay pots and the bread loaf pan. I hope that it will heat the small space and the heat will dump out into my lap, so to speak.

  9. pat
    November 30, 2014 at 7:51 am

    I live in Upper Michigan in a 20×25 log cabin I built. I burn wood but always looking for alternative heat sources I tried this. I built a 4’x4’x6′ box with card board. I got 2 6″ clay pots and hardware a candle in a jar and placed everything in my living room. Shut heat down, I placed blanket and pillow in box also, it was 7° last night and I stayed warm all night..

  10. Plan9
    December 4, 2014 at 10:58 pm

    ive hot a lot of clay pots that have been collected over the years. Many bolts, washer and nuts. I think I will construct 6 of these and try them out ony 6×8 greenhouse. Will put a wireless remote thermometer to check the temp. Maybe it will keep my winter veges and plants warm enough to survive the coldest temp in the central valleu of California .

  11. Carolinaprepper
    December 20, 2014 at 8:49 am

    Ive used several of these as aux heaters for my cold frames and we are still getting our lettuce from the cold frames.we have been lucky enough to seal and insulate our home built in the early 8o’s and with the oil lamps we use for ambiant light at night, have really cut out utilites. with energy cost looking like they will continue to increase in the long run thanks to the liberal agenda. thses will help in specialized applications.

  12. Mary DeCoff
    February 10, 2015 at 6:31 am

    We had a power outage during the November blizzard in Maine.
    My daughter put blankets up over windows and door in one room and heated it with multiple candles. It was quite cozy. I think this would work in an emergency and even harness the heat. Am going to try this week end here in TN when the artic front comes through here to suplement my propane heat.

    • Angel M
      February 20, 2015 at 11:12 am

      I live in TN also and I’d like to know how it worked for someone who actually built and used it. We didn’t lose our electricity but my cousin did for about 48 hours. This would also be a great addition to an emergency car kit if it works. Thanks!

  13. These can be very dangerous.
    March 21, 2016 at 6:50 pm

    These heaters can be VERY dangerous. The enclosure around the flame captures the heat and radiates it back at the candle. I made one of these out of tea lights and took regular reading with my FLIR i7 and within 15 minutes it combusted. My research would reveal that the ignition temperature of the wax was around 230 degrees C. The flame itself exceed the capacity of the camera around 270 deg C (519 F). Once the wax ignited the heat output increased substantially.

    I also found a video online of a guy who almost burned his boat down with one of these. I would consider this set up for an emergency situation only and to be supervised at all times with a fire extinguisher nearby.

  14. pat
    September 30, 2016 at 7:05 pm

    They work well. Be safe, use a fireproof tray and use your brain. Great in a pinch, grand under a large table to keep warm when dining.

  15. Mayhem
    December 4, 2016 at 8:03 am

    I am using one in my truck. I have not used the bolts just two pots and six candles and I have the candles in a mudding tin so they don’t spill or tip over. I am a Security Officer and sit in my truck all night. I am trying to perfect the the system.

  16. Gary Geiser
    December 7, 2016 at 5:40 am

    1 tea candle creates approximately 300 btu (MAX) no matter how you capture the heat it’s the same amount of energy. so if 300 btu’s of electric heat will heat the room then so will the candle.

  17. Antony
    December 19, 2016 at 12:52 am

    what kind of metal must the screw be?
    normal iron screw with galvanized paint over it or should be
    inox / stainless steel for plumbing ???

  18. karen
    December 20, 2016 at 11:14 am

    I am just reading this whole thread. I have a friend whose landlord doesn’t use heat at all. she’s freezing at home. I’m trying this out as I sit in my COLD garage. I have a $2 pot in an aluminium tray next to one foot. (three tea lights) and that foot is warmer than the other. so it might help a person. Definitely more than just candles only.
    more to be revealed

  19. Shari
    January 13, 2017 at 2:52 pm

    I made two heaters with slight variation of structure. The room had too much draft for it to be very efficient. i used a shallow cake pan, wire rack, tea light candles and two pots with bolt, nuts, washers. I will use it in my bedroom only, and think one will warm the space nicely for a few hours.

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