Hope this is the right area to post this question. I was talking to a friend of mine who has been using coal in a hand fired stove for many years as supplemental heat. I told him I was going to find and install a used auger fed boiler. He told me to be careful of the brand name because some boilers only use rice coal and you don’t get as much heat from rice as you do from the larger sizes. Is this right? It doesn’t sound right to me. A ton of coal should contain the same amount of heat no matter what the size. I could see quality of coal causing a variable but not the size.