In a masonry heater, a charge of wood is burned rapidly in one or two hours. The gases are drawn through long masonry channels until they get to the chimney. By this time there is no heat left in the gases as it has been absorbed by the large thermal mass of the heater. The mass then gently radiates the stored heat over the next 12-24 hours. The rapid burn is very clean, full combustion, so there is no creosote. This is the most efficient way to burn wood.
Visit the Masonry Heater Association website for more information.