The terracotta flowerpot + candle heater. Real talk :)

[nickdutch]

My early experiments in the candle and flowerpot heater have been interesting. In the end the system that seemed to work best was based on the bread baking tin with two flowerpots upside down, one within the other over the 4 tea light candles, but with the holes on both pots blocked up with plugs of aluminium foil. So similar to the one from the chap who worked for Practical Boat owner, but with both flowerpots holes plugged.

This is still an experiment, so I will probably refine the design with the passage of time. But heat is important especially in a world in which we are anticipating northern blocking, and this is something that we all need to know.

After a few hours of burning, I used oven gloves to remove the two pots from the bread baking tin stand and as I knelt on my knees with the inner pot now off the 4 tea light candles and off the baking tin, but between my knees on the tiles of the kitchen floor, the stored heat radiated from the hot terracotta flowerpot. The radiant heat could be felt penetrating my trousers and warming my skin and muscles. It was quite an informative experience. The terracotta pots really do radiate heat.

After that moment and as the pot started to cool, I cuddled it like a hot water bottle and it was very nice indeed.

But the question is how much heat was I producing with the heater and how much was I trapping and how can I use this to have meaningful heating in my flat?

According to wikipedia

“Based on measurements of a taper-type, paraffin wax candle, a modern candle typically burns at a steady rate of about 0.1 g/min, releasing heat at roughly 80 W”

Meaning that my four tea light terracotta flowerpot heater was a 80 W x 4 = 320 W heater, which would be ok for very close quarters if you don't mind the radiant surface taking ages to heat up. Either way 320 W was being radiated and convected. Interesting fact!

But lets try and put this in perspective and create a hypothesis based on the facts from wikipedia. If what wikipedia says is true, then you can't heat a whole room with a “heatstick” with a single candle under it (being a lousy 80 watts). It's a fallacy and it won't make your room so hot that you sweat unlike some youtubers claims. It's factually inaccurate unless a cheap flower pot from the garden centre of “homebase” is an over-unity device that draws power from another dimension.... However, not being a Time Lord, or a popular TV physicist, I can't comment on that.

My electric radiator which can keep my flat at a not too ghastly temperature in the winter (maybe 16 or more Celsius) is a 1500 W heater.

To try and generate something close to that would take 1500 / 320 X my baking tin, four tea light candles and two flowerpot heaters = 4.6875, so lets say 5. (being a total of 5 of the smaller flowerpots, 5 of the larger ones, and 5 cheep baking tins from the £1 shop to make the heating array).

5 X 4 candles = 20 tea lights = the equivalent of my electric oil filled heater.

Lets say each tea light burns for 4 hours. If you need 16 hours continuous heat, that means 4 separate burnings and setting up the heaters 4 times a day as a worst case scenario for a flat.

This is 80 tea lights a day which is still less than 100 tea lights a day. If you are lucky, you can get 100 tea lights for £1, thus making your winter fuel bills for space heating (not hot water) just £1 a day or less for a flat (hypothetically).

But the danger then is running out of oxygen, carbon monoxide poisoning and the like, not to mention the strange looks you will get clearing the shelves of the £1 shop once a week to keep you in fuel (tea light candles).

[hobo]

Thanks Nick. The tea lights in mine - Morrissons own brand - lasted 7+ hours. They were 2p each. They seemed a standard size....

[Plymtom]

One thing worth remembering Nick is wattage of a heater does not mean it burns that constantly, it has a thermostat, if it's an oil filled radiator type one as apposed to a convection one, then it works rather like the candles by retaining and radiating heat, rather than heating the air, which brings me to why we can then look at the system we are testing here and say, the candles will release the given quantity of energy covered or not, covering them is simply the difference between the oil filled radiator and the convector, so we are trapping the heat, delaying it's journey to the ceiling, where it's perceived benefits are low to the person on the floor.

[nickdutch]

One thing worth remembering Nick is wattage of a heater does not mean it burns that constantly, it has a thermostat, if it's an oil filled radiator type one as apposed to a convection one, then it works rather like the candles by retaining and radiating heat, rather than heating the air, which brings me to why we can then look at the system we are testing here and say, the candles will release the given quantity of energy covered or not, covering them is simply the difference between the oil filled radiator and the convector, so we are trapping the heat, delaying it's journey to the ceiling, where it's perceived benefits are low to the person on the floor.

This is an important point that I had quite forgotten. Thank you.