I watched some of the candle terra-cotta pot heater videos. The take away is the more candles the more heat. One of the YT video shows a Crisco candle made with a 32oz mason jar and it didn't do much heating if at all. A single burning wick can only put out so many BTUs regardless of how much crisco you use. Sure, you'll have a cheap light source for days but dont expect it to heat even a small room very well.