I can get coal for $45/ton, I haul and unload. That's the best I can tell you on coal. My brother is a mine boss, we presently get it for free. If coal isn't available burn wood. How much wood, that depends on your house size and if that was your only heat source, it is my opinion you will burn 2X more wood than coal. We heat our cabin with a Warm Morning 521, no other heat sources. I have a WM 521 sitting in my building ready to use as a back-up if ever needed and a cord of wood. Coal will create more of a mess than wood.