Abstract: A solar energy absorbing body has a plurality of discrete solar energy absorbing surfaces in a random arrangement providing a random array of interstices dispersed throughout the body through which solar radiation passes to strike the absorbing surfaces to become heated and through which a stream of air is passed to transfer heat from the heated surfaces. An effective absorbing surface is provided by fine glass filaments coated with a coating containing a thermosetting synthetic resin in which is mixed highly absorptive fine particles. Collectors containing the absorbing body have wall portions that direct a stream of air in particular flow patterns to and from the absorbing body so as to obtain maximum heat transfer.