methods and apparatus for burning fuel from a supply of solid fuel positioned at one side of a grating light a layer of the solid fuel at the grating to discharge combustible gas . such discharged gas is drawn through the grating to a side of the grating opposite the mentioned one side and such drawn gas is burned at the other side of the grating . attainable temperature of said grating , acting as a primary grating , is increased by providing a secondary grating spaced from such primary grating and located between that primary grating and a fire chamber . the methods and apparatus of the subject invention enable particulate , pelletized and other solid fuels , as well as combustible refuse and garbage , to be burned at an efficiency and convenience similar to the combustion of heating oil , and yet provide heat at a fraction of the cost of oil and gas heating methods .