# Cheap Flower pot Heat



## phideaux (Nov 7, 2015)

Im gonna try this , just to see how much heat it will give..

Cheap enough, makes sense, nothing to lose.

http://homemadeenergy.club/how-to-heat-up-your-room-with-only-5-bucks/

Jim


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## tsrwivey (Dec 31, 2010)

I've seen something similar but have never tried it. Give it a shot & let us know how it works!


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## cnsper (Sep 20, 2012)

That ought to work great at 60°, but at -20° probably not so good. Ever notice that they never mention the ambient temps or the rise in temp? Might be good for heating some soup though. 200° pot should heat up some soup really well.


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## phideaux (Nov 7, 2015)

My wood stove absorbs the heat, from a piece of woo, and radiates it back out , replaced my furnace.
Works great BELOW 50 deg temps, all lthe way down to -20deg.

This would be a smaller , so to speak, wood stove. Just much smaller scale, for smaller areas. 

Thinkin outloud...



Jim


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## Caribou (Aug 18, 2012)

There are three ways to heat, conduction, convection, and radiation. 

Conduction is the direct transfer of heat like a hot pad might provide or when you put a pan on the range.

Convection is the indirect transfer with water or usually air. We heat the air with conduction and the warm air heats us and everything else.

Radiation is the direct transfer of heat at a distance. Our sun is the prime example of radiant energy. Radiant heat can travel through air or a vacuum. 

The way this thing works is through radiation. By converting the candle into radiant energy it is absorbed into your body more efficiently. It is called 'felt warmth', the room isn't any warmer but you are. The same is true around a camp fire. You are not warming the air significantly but you feel warm. 

Some years back I put an inch and a half of rigid insulation on the outside of my home. I was able to turn down the thermostat by two degrees and maintain the same level of comfort. The warmer walls provided more radiant heat and I felt warmer. While air temperature is important our comfort is largely determined by radiation. We receive radiant heat from the walls, floor, ceiling, chairs, tables and everything else in the room.


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## Grimm (Sep 5, 2012)

Here is a video with all the math and science about this "heater"


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## cowboyhermit (Nov 10, 2012)

Grimm said:


> Here is a video with all the math and science about this "heater"


Thanks for the video, this comes up a lot and I wish there was a good response to link to. Unfortunately, that guy missed the entire point of the thing. He looked for the number of btu he needed to heat all the air in his greenhouse, then tried to calculate how many btu the "heater" put out. He failed on all accounts. Putting a kettle on top of the heater will only measure a fraction of the heat given off, while all of the heat is usable in an enclosure, etc. etc. If he wanted to know the BTU the things put out all he had to do was look up the btu/pound of the wax.

Anyways, like mentioned, all these things do is try to capture and redirect heat to where it is needed. It is similar to infrared heaters used in shops and the like, rather than heating all the air in the space, most of the heat is directly transferred to the objects it shines on (which in turn of course heats the air to some degree).

Basically, if you light a candle in a room, most of the heat generated will travel straight up, and be of little benefit. However, objects in the space surrounding one of these "heaters" will absorb much of the heat with less of it going up (making the measuring in the video more ridiculous).

Realistically, these things don't do much, certainly in terms of warming a whole room. They can put bits of heat in particular areas though, instead of the ceiling.

Maybe a better analogy would be a brood lamp, or an animal heat pad, they put out very little btu but do a great job at warming what is required. A fan forced heater of similar btu would be very inefficient, like a 12V dashboard window heater (they do very little). Unfortunately, the flower pot units are not nearly so good at directing the heat for most situations.


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## Grimm (Sep 5, 2012)

cowboyhermit said:


> Thanks for the video, this comes up a lot and I wish there was a good response to link to. Unfortunately, that guy missed the entire point of the thing. He looked for the number of btu he needed to heat all the air in his greenhouse, then tried to calculate how many btu the "heater" put out. He failed on all accounts. Putting a kettle on top of the heater will only measure a fraction of the heat given off, while all of the heat is usable in an enclosure, etc. etc. If he wanted to know the BTU the things put out all he had to do was look up the btu/pound of the wax.
> 
> Anyways, like mentioned, all these things do is try to capture and redirect heat to where it is needed. It is similar to infrared heaters used in shops and the like, rather than heating all the air in the space, most of the heat is directly transferred to the objects it shines on (which in turn of course heats the air to some degree).
> 
> ...


I posted this because it had some decent math and basic science but I agree not acurate by a long shot.

I read an article debunking these "heaters" a while back.

http://frumpyhausfrau.com/recession-survival/tealight-room-heater-reviewed/



> "Heat an entire room for 8 pence a day!" says the title of a video making the rounds on social media. After watching the video, I could already see some problems with this claim. But the heater looked useful, so I decided to try it out, and see what it COULD do.
> 
> A link to the original blog post with the video that I watched is at the end of this article.
> 
> ...


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## Texas (May 14, 2013)

Saw these last year and built one. Never even got the outside pot hot. Plus made a lot of carbon to clean up to use the pots for the intended purpose. Waste of time!!!


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## cowboyhermit (Nov 10, 2012)

mike_dippert said:


> ...
> The heat from a candle's flame is already radiant energy. ....


Much of the heat from a candle (or a fire) is not radiant energy, but in-fact gasses produced in the combustion process. The gasses typically rise very quickly in a calm room, and that energy that is a significant percentage can be turned to radiant energy. It is significant as a percentage of the energy but not so much in absolute terms, in the case of a candle.


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## fteter (May 23, 2014)

As a younger man, I backpacked quite a bit. Especially loved backpacking in higher elevations during the winter.

One piece of "must have" gear I always packed was a candle hand warmer. Just the thing to warm up the hands on a frosty morning. More of a creature comfort than a piece of survival gear.

These flower pot heaters strike me as being the same type of thing. They won't heat your house. Not even a room. But they might be good for warming up hands or, as pointed out earlier in this thread, a can of soup. Again, probably more of a creature comfort than a piece of hard-core survival gear.


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## hiwall (Jun 15, 2012)

From the 'net....................



> 250-300 British Thermal Units (BTUs) in a standard candle like a tea candle. More or less with larger or smaller candles.





> the steady-state heat release rate from the candle was calculated to be 263 BTU/h.


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