|Ikea GLIMMA unscented tealight candles|
So, that aside .... here is the very cool trick.
Through the use of tea-light candles, which are pretty ubiquitous, two clay flower pots, which are even more ubiquitous and a cake tin it is possible to make a very simple radiant space hater. Obviously, as with any fire you will be wanting to do this in a ventilated area, carbon monoxide is not your friend.
By placing one pot over the other, with the candle inside, you create a space that not only traps the radiant heat of the candle, as it heats up the inner pot, but all that heat is not only stored in that inner pot, but due to the air space between the two pots, convection takes hold and you get more bang for your buck. The cake tin gives you a stable, fireproof base, allows you to move the rig once lit, and also provides a venting space for the candle to "breathe".
Cool air flows via the open top of the cake tin the two sets of nested posts are resting on, and between the base of the outer pot over and around the inner pot, then up through the drain holes and up into your room. This action not only draws heat from the inner pot heat-sink, but also moves that air through the room, spreading out all that heat more efficiently than a stand alone candle like a passive fan.
The tea light candles are just a convenient size, cheep and plentiful but any candle that fits in the pots you use would do.
Here's the original YouTube clip in the article, demonstrating the heater in effect.