A candle heater is one of the most sustainable and environmentally friendly ideas we’ve ever heard of. It is also a very cheap and efficient alternative to traditional heating systems as it will cost you less than 15 cents per day to heat up an entire room. The idea behind it is very easy and it can be made at home by anyone, you just need to have some Terra-Cotta pots, washers, bolts and candles. Basically, you will be building a small radiator which will be powered by the candles and the heat inside the pots. You can find a detailed explanation on the following link and step by step instructions on how to build this simple, but efficient heater yourself.