Abstract: A fuel burning stove or furnace wherein combustion of fuel is more complete resulting in a greater amount of heat generation and a cleaner combustion residue. The stove includes a stove housing defined by side walls and top and bottom walls and having an unobstructed combustion chamber. A flue has a flue passage to the combustion chamber at the lower portion thereof beneath the normal combustion area within the chamber. Unburned gaseous products of combustion rise toward the top of the chamber and are trapped and forced back downward through the chamber into the flue passage. As they pass again through the flame of combustion, the unburned products are burned. The result is more efficient combustion and a cleaner combustion residue. The residue is less pollutant and is safer in terms of avoiding chimney fires.