A BTU is a BTU is a BTU. The law of conservation of energy applies to the argument. The amount of heat produced by a smallish flame is the same whether you're heating the air (convection) or heating the things around the space (radiant). The BTU output of a candle flame, burning paraffin wax is only about 9BTUs. That's just 65% of the BTUs produced with an electric 4-watt nightlight bulb. A candle burning soy wax only produces around 6BTUs. A typical candle isn't going to create any kind of meaningful heat. However, with that said, Robert is using vegetable oil, which is more closely associated with soy than with paraffin. He also has a flame which is at least 1.5" in height and a wick up to 1/2" in diameter. It's going to output orders of magnitude more heat than a typical candle. For comparison, a typical hurricane lantern with a half inch flat wick can output as much as 900BTUs/hour when burning kerosene. That kind of heating can definitely warm a small room with radiant heat. In 2020, I kept a 125CF polypropylene (PE) greenhouse at 68F when the outside temperature was -10F (a 78F temperature differential on opposite sides of flimsy plastic!!) using a 1500watt oil filled radiator space heater and (3) 1-K kerosene hurricane lanterns to supplement the electric space heater. The argument as to whether a terra cotta pot heater can work or not, has more to do with the size of the flame than anything. A typical candle or tea light candle just doesn't output enough BTUs to accomplish much of anything. The wick is barely a 1/16 of an inch in diameter, and the flame is not much more than 3/8" tall. But if you create your own candles -- vegetable oil, kerosene, paraffin oil, diesel fuel or even vegetable shortening -- with a quarter inch round wick or larger, or multiple quarter inch round wicks, then that terra cotta pot heater will work like a charm. As BTU levels rise, so too will fuel consumption. You'll get the most bang from your buck with diesel fuel, once you overcome its tendency to gel in cold weather.

Hi I know this is probably a stupid question, but what is a water jacket?

@@jude7321 might be a heat exchanger?

@@stonedsavage7814 Hi. Thanks for answering my question but I don't know what that is either. Sorry for being so ignorant.

@@jude7321 its actually a bath jacket

oh neat!!

ahhh - you noticed that lol - nice one mate

cheers mate

I've changed my mind back and forth on the terra cotta heater. I think it captures some of the heat that would otherwise just go straight up to the ceiling and made a spider up there think it was Chinook season. It doesn't add one erg of energy given off by the flame, but it re-directs some of that energy sideways to where people are. It'll feel much warmer next to it with a metal or ceramic radiator absorbing and re-radiating the heat to the side. At first, I thought it might be the heat mass of the clay pot extending the release time of the heat, and it would continue to give off heat after the candle was extinguished, but it'd only have as much heat stored up as its heat capacity times its mass would allow, and it's not really that much mass, and the temperatures achieved aren't really that high. You need a lot of mass and a lot of heat put into that mass to do a whole lot after the flame goes out. I just think there's more to the re-radiation of some of the heat, laterally, is what makes it out-perform a burner, alone.

@@ThinkingandTinkering i tried this with the carbon fiber and lamp oil but the fumes were strong… please let me know what brand of fiber you use…

Overhead radiant heat is much better than heated floors for many reasons, although it does mean you (and your cats) can't stretch out on a nice warm floor as quickly. But we're more accustomed to radiant heat from above, because of the sun, and it does warm the furniture. Added bonuses include much lower installation cost, less wear and tear on the system -- and, if it leaks, you know right away and can get at it to fix it much more easily and cheaply.

that is a great add - cheers mate

You can still buy candle powered versions. Now that batteries and LEDs are so good for light; they're basically only advertised for their heating properties.

for sure

Would it be difficult to put a fireproof cap on a cotton wick? Actually, I don't see the problem with ordinary wicks, but I may be missing something.

it was a good idea mate - thanks for sharing it

@@MichaelAckerman Ordinary wicks and homemade wicks are fine. Curious? Why put a ceramic cap on a wick, do you mean like a terracotta wick to spread the heat? If so, yes; or glass for light. Not sure if any form of glass will radiate heat but if so, it gives the added benefit of both radiating heat and producing visible light 🕯️!

@@MichaelAckerman ordinary wicks burn up. The carbon fiber wick also does but very very much slower leading to him calling it the forever wick.

Will Carbontape work? or is that something else.. Carbontape is normally used with epoxy to make object strong.

cheers mate - from the previous video and comments I thought it would be good to go a bit more into the theory

Thank you! Cheers!

“Hi!” “That’s awesome!”

Yes! I was also thinking along the lines of "That's awesome"!!!! I also think Rob needs to trademark that laugh! :-)

lol - cheers mate

nice - cheers mate

cheers mate

Can you post a link to what you bought please?

Can you tell us the EBay "sellers" info , please ?

awesome mate

cheers mate

cheers mate

cheers mate

there are just a ton of solutions when you look ate that is for sure - thanks for the reminder of that - cheers

yes i was too thinking that..

can use 3 tea light candle lanterns too i think?

nice one - thanks for sharing mate

cheers mate

cheers mate

That's what ceiling fans are for...

@@andyreact hahahahaha, yes but not as effective as floor vents. Especially in the summer months. You're circulating hot air down onto yourself 😉👍

@@orpheuscreativeco9236 Most ceiling fans have a switch so that you can reverse it. One setting works better in the winter and one works better in the summer.

@@justinw1765 Yes, they do. 👍 You're not quite understanding the point, and that's okay.

thank you for sharing that idea too mate - how about a bit further pull the air from the attic space?

Oh, so kind of like using cooling fins, but for the reverse purpose? Nice!

cheers mate

cheers mate

Hmmm...CPU heatsink on top of the rod?

but with the double pot you take away the radiation heat and you go back to convection heating, wich means you could just as wel use the tealights out in the open i think.

@@gabbermaikel I found it to be warmer with the double pot method than with just the tea lights. Four tea lights got the internal pot to a high enough temp to be painful to touch. Spread over the surface of the pot it could heat a larger volume of air. If I was warming my hands I'd go with one but if I wanted to warm the room, slightly, two works better so far as I've seen. Just one heater won't make much of a difference but it took the sting out of a cold morning in a single room. Edit: a word.

lol - there is always a drawback mate

This is basically what I wanted to add, if yer building an radiating heater, shiny is bad, you want to radiate, so one must chose a proper surface for that. Clay probably has better emissivity, using the graphite cover trick presented by Robert in another video is a good idea. Graphite, being black and somewhat matte should be a good radiative surface treatment. Graphite is also such a thin layer it doesn't pose much of an isolator.

lol glad you liked it mate

They will but terracota holds the heat longer after the flame is extinguished.

lol - absolutely mate - I really don't understand why folks can get so upset about what is really pretty trivial if you think about it

@@ThinkingandTinkering Agree, good saying there. Perhaps it's another type of ventng system. People vent hot air through small things, cos they can't reach the big things.

Ur gonna want to figure out how to make sure to put a seal on the bottom saucer. It a hazard if fuel can seep through, even worse if it is on fire as it seeps

see you in spring mate!

" louvered rings around the candle flame " ; find your self a trashed air cooled motorcycle jug or old V/W cylinder .

@@wendellpowell2653 This was the first thing I thought of Wendell. But I realized right away that the cooling fins are at the wrong angle. Using lovers that are on say a 45 degree angle will let the heat do its thing and rise vertically. This way you can make the chimney as tall as possible with the flame size you are working with. Just my idea. Hope someone runs with it and experiments to improve this type of heater. Peace

This got me thinking about stacked cookware, where the bottom pot warms the pot above it enough to cook in that too. Normally you cook about 2 or 3 pots high, but for a heater, you might be able to go higher.

you must make it mate - I would love to see

@@colleenforrest7936 RIght on Colleen. This is a real logical way of thinking.

Doc, I like the idea of alcohol as it can be made from almost anything stored ran in engines. Im too tired to make all the calculations but i worry from direct heating some heat is lost from cooling effect of the evaporating alcohol. I guess this is true for all fuel. A friend of mine had 6 guage copper wire running from flame back to the fuel to keep it warm.

@@mike289homebuilt5 I am not that worried about a few degrees loss. I'm burning alcohol in a canful of sand and heating another can.. you can probably find it on my channel by typing in alcohol

nice one mate

cheers

nie - cheers mate

good one mate

I will have to give it a go mate - cheers

personally I think there are some interesting ideas to take away and use that's for sure

nice one mate and thanks for sharing

Could Strongbow cans heat water for drinking, if not what would be safe to heat water in for food preparation?

@@jude7321 I use a camping kettle, small, strongbow cans are for dishes and heat.

nice add mate - thanks for sharing

CO2 is fine. CO on the other hand can get quite toxic quite fast.

as Justin pointed out mate - CO2 is not the big issue CO is

cheers mate

nice idea mate - cheers

I will check it out

Not strange at all. Vapes are literally just a battery and resistance wire.

lol - I have taken quite a few apart mate but nice pointer for others

yes, excellent idea, now you're talking

nice - cheers

I'll look into it mate

I was thinking about soot being one of the least reflective materials. Might be just what's needed and the heat source actually producing it as it burns is genius

that is interesting and kind of backs up what I am saying - cheers mate