Fall is here again and winter is approaching inevitably. So the annual posts on clay pot candle heaters are prospering again as they do every year. With germany’s energy crisis becoming more and more obvious, lots of untrustworthy and even mainstream voices rise recommending tealight-ovens as an alternative means of heating. In the light of a recent discussion, let me clarify things on this issue a little bit if you allow, ok?
I have one of these contraptions (home made of course) running in my greenhouse – they work fine and as long as you know what they’re really doing you can use them adequately and rely on them properly.
What they don’t do:
They don’t magically multiply energy. An average tealight candle gives off an output of around 30 watts. No flowerpot on earth can increase that energy in some mysterious way out of nowhere. So 30 watts power will always be no more and no less than 30 watts power, but…
What they can do:
They aggregate heat. A simple candle flame instantly gives off by far most of it’s heat directly upwards (and away) – very inefficient. In contrast, the earthenware flowerpot’s mass heats up from the candles below and stores most of the energy. This heat can now be radiated evenly in all directions and over a longer period of time, thus distributing it way better.
The flower pot maximises the efficiency of the burning candles, it does not and can not produce more power than a standalone candle would. If it get’s reasonably cold, rather invest in a decent greenhouse heater.