Gefest 45 (M) - higher weight cast iron heater. Furnace radiator protrusions directed to the depth of the furnace increase the area of contact between the fire and the furnace and the efficiency of heat transfer. Cast iron needles increase water evaporation. By opening the top lid of the heater and pouring water on the hot stones, you will get plenty and soft steam.
In the second furnace chamber, the combustion of pyrolysis gas increases the combustion temperature, which increases the efficiency of the furnace by up to 90%.