A Simple, DIY Thermal Mass Tiny House Heater

Not too long ago I did a video where I used a couple clay pots and small candles to make a small space heater with the idea of heating a tiny house. This idea had been floating around YouTube for awhile and I wanted to see how it worked so I could share it with you considering most of are interested in small spaces, heating them when necessary and doing it on the cheap.

The results were pretty good (at least I thought) but I still wasn’t completely convinced that the clay pot heater generated enough energy to make a noticeable difference in a tiny space’s room temperature.

So building on the tea light heating idea, I decided to try a new concept that I had been marinating on for awhile combining it with the practice of using thermal mass (using heavy materials to soak up heat) to heat a space. The results I feel were impressive and on this video we have the numbers to prove it.

I believe a heater like this has the potential to effectively heat a small space that is well-insulated or extremely small space (think micro cabin) that isn’t.

Once the heater was warmed up, it reached temperatures over 200 degrees!

Here is the video that gives you the idea behind this little heater and how to easily build one for yourself:

Here is a breakdown of the project cost:

  • Cast iron skillet: $3 at a second-hand store
  • Clay fire brick: Free, found on Craigslist
  • Aluminum bucket stand: $3 at Home Depot
  • Tea Light Candles: $3.99 for 100 at Ikea

    Taking this idea even further, if you were willing to use even more candles you could use a cast iron dutch oven and fill it with more clay fire bricks that would eventually dispense even more heat once up to temperature.

    Be sure to subscribe to The Tiny House Listings YouTube Channel for more cool tiny house/space-saving/money-saving/alternative energy ideas

    Do you have ideas for building on this idea, or have you tried a DIY heater for yourself in the past?

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    Category : Blog

9 Comments → “A Simple, DIY Thermal Mass Tiny House Heater”

  1. Brandon

    Dec 04, 2013

    I tried the clay planter last week and it didn’t radiate heat any further than an inch from the pots.


    • Garth

      Dec 07, 2013

      I tried it too. It took at least half hour to get going (as the video said), and then I would say it was about 1/3 to 1/2 as effective as a standard plug-in electric heater–which means not very effictive–but OTOH it is much, much cheaper per hour, and of course the electric heater is not an option for off-grid solar-powered electricity at night. It definitely takes the edge off if I put the tealight-powered heater under my steel desk where the electric heater would be a big overkill.


  2. Laura

    Dec 05, 2013



  3. Shell

    Dec 06, 2013

    I would so love to try either one of these to keep the heating bill down in my place. I could just use it in my bedroom. Problem is I have a cat. That makes me very nervous for sure. : (


    • 2BarA

      Dec 07, 2013

      I”m not surprised that works so well. About 40 years ago I used to do a lot of wilderness canoeing. One couple in the group used to put a can filled with sand on their one-burner Primus stove and let it get really hot. After they turned off the stove, the sand retained heat which it emitted for hours, keeping their tent warm. Your solution, and theirs, are much more effective than the flower-pot idea.


  4. Chris Cook

    Dec 07, 2013

    It is a physics question. The mass of the brick and iron will radiate the energy slower than the candles alone. The btu output of the candles can’t be all that much. I live in a 200 square foot well insulated tiny home in North Dakota. The outside temp last night was minus 29 with a little wind. (Wind matters). My home needed about 7000 btu’s to hold 70 degrees. (7000 btu’s would be 1.5 small electric portable heaters).

    The main way to keep a tiny home comfortable in my opinion is to insulate it with spray foam 2lb polyurethane foam, disconnect the framing from the outside walls, and add MASS.

    The mass helps keep the temp when the door is opened and moderate the swings between night and day, summer and winter. This can be accomplished with water in tanks.


  5. Marsha Cowan

    Dec 07, 2013

    Great idea, and though I am not in that room, I’ll bet it is warming up. Just one suggestion, and this comes from the protective mother side of me–either use a cast iron skillet without a handle, or turn the handle away toward the corner or wall so no one will run into it. Handles on pots–number one cause of stove accidents with little ones. Just a suggestion! Love the idea!


  6. Chris Cook

    Dec 08, 2013

    I am following up on my comments above. I looked up the BTU output of a candle and it seems that 300 btu is a reasonable output assumption. Keeping that in mind my extreme weather case outlined above would need 21 candles to keep warm.

    That would Need air exchange because of the carbon monoxide given off. It is reasonable to expect that a well insulated home in 20 degree or higher outside temps will easily be able to use this system for heating.


    This is making me rethink my heating system for my tiny home. Maybe a direct vent, micro stove that uses wood pellets. There are cast iron stoves available for cheap, (under $200 on Amazon), that operate on wood. Just use candles or pellets and a large pot of water or bricks. The candles will allow a much more controlled and lower heat output, since these stoves are typically too powerful. The nice part is that they vent, making them safe to use.


  7. jocelyne

    Jan 07, 2014

    this works fairly well, but I am having a hard time keeping the tea lights lit.
    I have to move my cast iron pot over to let a gap, which means of course
    the heat escapes . . do I need more holes in the bucket?


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