Firewood heater is the popular means of heating and can be applied for the home heating and industrial use. It employs a convoluted flue path running through dense thermal mass (often a combination of brick and cob) to soak up and store the maximum amount of heat, releasing it over time. Efficiency of the fire wood heater is depends on how wood is converted to heat with little pollution, while effectiveness comes from being able to store that heat over time.