Abstract: An improved flat plate solar energy collector of integral construction capable of mass production in which metal tubing is eliminated. The collector includes a stamped planar tray and a radiant energy absorber plate connected together to form the inlet and outlet fluid header and the innerconnecting channels therebetween. The planar tray and absorber plate are mounted in a molded insulated housing which includes integrally a storage tank. A fluid medium such as water is heated by solar radiation and circulated through the collector to the storage tank by thermal syphon. Elimination of conventional tubing greatly reduces fabrication costs and increases absorption efficiency.