There are a lot of videos on how to make clay pot heaters, but this one is simple and easy to follow.
With a pot, some screws and a couple of candles, you have a cheap and aesthetically pleasing mini space heater, as the pot will capture the candles' heat, letting it slowly build up.
uhmm...no, it doesn't work like that
fan has not enough pull power to suck the colder air from floor level, you need to force warm air that is stored on ceiling level down so it mixes with the colder
that is much more efficient way of heating up large air volumes