Thatched Hut with a Three Stone Fire

This is a cut-away view of a thatched hut with a small three stone fire. The fire needs to be small because there is no chimney; the smoke merely filters through the roof or through a hole. A large fire would create too much draught that could carry sparks up to the roof and start a fire.
The three stone fire has been used for many thousands of years. It combines an efficient combustion area with a stable platform for a cooking pot. If used correctly, with good quality dry wood, it can burn with very little smoke. Poor quality damp wood or too much wood can create more smoke than can quickly escape through the roof . The smoke can fill the hut and poison the occupants. These inefficient open fires cause health damage through indoor smoke pollution, burn far more wood than necessary and waste the energy of the people who gather the firewood. This in turn leads to deforestation as people cut down the trees around them for fuel.