Critical review here: http://tinyhouseblog.com/heaters/kandle-heeter-candle-holder/
I bought one of these and, sadly, Iâ€™d have to say donâ€™t waste your money. As Tom said above, these little â€œheatersâ€ put out no more heat than a plain old candle that costs a fraction of what this heater does. Also, the creator is very specific about what type candle can be used â€“ it must be a votive in a glass. I found the unit melts the candle each time the heater heats up and the candles really donâ€™t last as the creator suggests. Also, the heater seems a little top-heavy and has a tendency to tip over easily. Itâ€™s a great idea and a wonderful gimmick and I really wanted it to be cool, but Iâ€™m sad to say, it really doesnâ€™t work.http://www.greenoptimistic.com/2008/11/06/candle-room-heater/comment-page-1/#comments
Clearly ideal for folks with no understanding of physics or thermodynamics whatsoeverâ€¦
FWIW, ALL the heat from the candle ends up in the room with or without the decorative ceramic junk over the top of it. All this gadget does is trap some of that heat closer to the candle where you can notice the ceramic getting hot. It can not and does not increase the efficiency of heat production, heat transfer to the room, or the final temperature of the room. That is, it does nothing at all of interest or value. It does add a certain flowerpot and junk decorative aspect, if you like that sort of thingâ€¦ and it will tell all your brighter friends that you are clueless about physics and heat.
And a counterpoint:
I get that comment pretty often from those who have never been around fire heating systems. They become so focused on the â€œphysicsâ€ that they lose sight of the practical. A candle creates an invisible chimney â€” put your hand above a candle flame â€” that very hot air is rising straight to the ceiling, and then out of the room. Oh sure, it is still in the room, but who lives on the ceiling?
What the radiator assembly does is short stop the heat rise and concentrate the thermal energy into a solid piece of steel, this becomes an active heat sink that is constantly radiating into the surrounding ceramics. I know Mr. Know-It-All dosenâ€™t get it, but this thing really does work to keep real usable space heat at human level. Well over a 1,000 are out there, and orders still come in.
And counter-counterpoint (don't you love the hivemind?) This guy seems to know what he's talking about:
Juawtawn: You are confusing radiant heat and convection. When air moves past a hot surface and becomes hot this is convection heating, not radiant heat. Radiant heat has nothing to do with air currents and can function in a vacuum.
Admin and the rest: Take some thermo dynamics classes.
Let me clear this up for you. There are three types of heat transfer. The candle produces all three.
1. Direct contact or atomic excitation: Here the fast moving atoms in one material (which is all that heat is) cause the atoms in another material it touches to move quicker. Touch a pan or a light bulb or your driveway on a sunny day and youâ€™ll experience direct heat transfer.
2. Convection: Air moves by something that is hot and makes contact. Heat is transfered to the air by direct contact. The air than moves and contacts another object and transfers it heat to that new object through direct transfer.
3. Radiant heat: This can also be called inferred heat. Basically heat is transfered as a light wave. The excited atom drops an energy level and releases a photon in the inferred wavelength. When this photon hits something(a surface or even air)it transfers its energy into kinetic energy of the atom (or heat). This is how the sun heats the earth.
Now lets apply this understanding to this concept.
Anyone with any understanding of physics knows that you cannot add energy with this device. So the idea that you can raise the temperature of the room further with this device than with just a candle is clearly not possible, and a false claim.
A separate claim that can be made is that it is changing the heat transfer mechanism. Candles or any open flam for that matter transfer heat in all three ways.
I have seen some people here make comments about the hot air rising from a candle(convection transfer) so all the heat is at ceiling level and basically useless. This is true with the clay pot set-up too. It may not be as noticeable since the heat energy is dissipated over a larger surface resulting in a wider column of air with a lower temperature. A column of air with 4 times the surface area of another column but with 1/4 the temperature of the column is sending the same about of heat energy to the ceiling. In the end you are transferring the same about of heat to the ceiling just over a larger surface area. The end result is that heat rises no matter what. The same amount of heat travels to the ceiling.
Claims that it increases radiant heat are completely unjustified as well. The truth of the matter is it actually produces no radiant heat. The true test of radiant heat is can the heat be transfered without a medium (some type of matter). If there was a vacuum between me and the candle I could only detect the radiant heat. If I put this pot contraption behind a vacuum I would detect no radiant heat. The reason for this is because the temperature is to low. The quoted surface temperature of 140F-180F is no where close to the temperature needed to produce radiant heat in a clay material. What you might think is radiant heat is really just convection heating of the air around the pot.
This being said, even if this device was able to convert 100% of the heat energy into radiant heat (which clearly is not the case)a candle does not produce much heat. Also the notion that using a candle to heat your home is some how clean is ridiculous. A candle is one of the dirtiest burning fuel sources there are. Want proof, hold something over it and see how fast the suit accumulates. It may not produce as much pollution as a coal plant but it also produces a lot less energy. You would pollute less by creating that same amount of heat with your regular home heating system.
Conclusion: If you want to feel warmer turn up your thermostat, thats what itâ€™s their for. If you want to burn a candle do it for its beauty or scent not its heat production capability.
And the inventor addresses "Deedle" (author of the above):
The Kandle Heeter tm Candle Holder â€œworksâ€ â€” it does what it was/is intended to do, it harvests the normally wasted energy of a burning candle and makes it available at human level. Put â€œkandle heeterâ€ in google and read the reviews, there are several glowing reports of folks who were/are amazed at the experience. Watch the videos.
The key to it all is the solid steel inner core, something not at all well addressed in the above comments. Steel has the ability to approach the temperature of its heat source. A candle flame burns at 550-600 degrees Fahrenheit â€” so the steel inner core will heat up to 500+ degrees. That Is HOT! So now instead of just a small one inch candle flame at 500+ degrees with no thermal mass we have almost 3 ounces of solid steel (think thermal mass) at over 500 deg! That creates a very nice thermal â€œheat sinkâ€ that is constantly giving up its heat into the surrounding ceramics, and is constantly being â€œreplenishedâ€ by the burning flame.
And on, and on, and on.
BTW, I've just been reading a biography of Jack Parsons, who was one of the founders of American rocketry. He's a far more important figure than Robert Goddard, not that you'd know it from the history books. Anyway, Parsons was deeply into magick and the occult, seeing no conflict between that and his research at Caltech and JPL.
Clearly, they stopped making Polymaths a few decades ago.
One of the characters in the book was a professor at Caltech who believed that rocketry in a vacuum was impossible, because "There was nothing to push against".
This guy (forget his name) was the head of the Physics department, circa 1935.
Experts. You've got to love them.