Heat is the transfer of energy between two systems. In the case of wood burning, the transfer occurs between the wood and the room. There is only so much energy in 40 lbs of wood. I agree, a stove and a MH transfer energy in differnt ways. More specifically, the ways in which heat transfers (conduction, convection, and radiation) are in differnt proportions. However, short of something magical that breaks the laws of physics, the amount of energy in a given quantity of wood is fixed--so I don't see how the mason could be correct if making a comparison between a MH and an EPA wood stove.