Abstract: An air-heating appliance is described which uses used engine lubricating oil as a fuel. The oil is fed by gravity to a burner consisting of an open cylindrical pan having a perforated side-wall and which is divided horizontally by an apertured fire plate. The pan is surrounded by a cylindrical casing which is spaced from the walls of the pan. A flue duct is arranged concentrically with and extends from the open top of the pan and is provided with jacket to define a heat exchange passage around the flue duct for air to be heated. Air flow through the heat exchange passage is induced by a fan and is directed and redirected in the passage by angled vanes disposed therein. Initially, the oil is ignited by an electric heating element which is switched off once self-ignition conditions pertain.