The romans heated their huge bath houses with wood. They built the buildings on stilts and with hollow walls. There are pictures and videos of the furnace rooms with huge fire boxes. They burned tons of wood a day.
I use a RMH to heat this shack and on average for the past 4 years. Only burn 150 pallets a season. Helps when you live in the desert and if this house was an earthship I would use even less. The pallets are free and take little bit of work turning them into splinters. In fact I need to make some splinters today. You can see the size of the splinters in the picture I posted above. What is cool about the RMH. That just about any thing will burn in them. Sticks and stems news print, junk mail. If the power goes out you still have heat.