Question: I still have my H-II HearthStone....it's like a piece of furniture in the garage. Do you recall the coal kit that Hearthstone marketed for it?? Was it any good?? And, would you say, as a rule of thumb, that it was/is necessary to line the cast iron stoves with firebrick to protect them from the high temps encumbent with coal fires?? Answer: Brian, the short and long answer to this is that the coal conversions of the early 80's, including those from Hearthstone, Vermont Castings, Comforter, Jotul and others.....are not worth your while for a number of reason. At best, all factors being perfect, they barely worked. In many cases, they did not work at all. The terms "kludge" "Jury Rigged" etc. come to mind when thinking about these kits. Hearthstone, to my knowledge, has never made a decent coal stove or conversion. Vermont Casting did finally produce a Vigilant II coal stove which is fairly decent. The summary is: If you want to burn coal, buy a good coal stove. A good coal stove is generally NOT a good wood stove and vice versa.