Abstract: A recuperator of simple design constructed from a hollow tube. A penetrating tube is formed of a hollow tube, preferably of stainless steel, closed at one end and open at the other end. The open end is cut and welded, or otherwise secured, to a perpendicular hollow tube which introduces and expels ambient air. A divider wall is disposed within the penetrating tube to force introduced ambient air along the length of the penetrating tube before exiting the recuperator. This arrangement exposes the ambient air to the heated surface of the penetrating tube along its entire flow path, substantially twice the length of the penetrating tube. A spiralled strip of 14 gage stainless steel may be disposed within the penetrating tube to enhance heat exchange between the penetrating tube and ambient air flowing there within.