Abstract: Disclosed is an improved flat plate solar collector module for use in a solar energy utilization system. Each collector has a housing with an evacuated chamber defined therein. A transparent planar wall forms one side of the chamber and a radiant energy absorber with flow passages therein is supported within the chamber thermally insulated from the housing. Heat exchanger flow conduits extend from the absorber and through the housing without contacting the walls of the housing to allow circulation of heat exchange fluid through the absorber with minimal conduction heat losses.