Abstract: A lightweight, low cost, solar heat collecting system is provided for use with homes and other buildings. Solar heat collecting panels are mounted on a roof or other support and connected to the building's heating system. A liquid black body medium is pumped to the elevated upper end of each unit and is allowed to drain down through each panel by gravity feed back into a storage tank where the heated liquid is circulated, on demand, through the building. Each heating panel is comprised of a rigid foam plastic frame having a back wall over which is disposed a reflective stratum. A sheet of plastic material having a black surface is bonded to the reflective stratum along spaced parallel lines to define a plurality of parallel channels extending lengthwise of the panel. Manifolds are provided at opposite ends of the panel to feed the liquid into and drain the liquid from the channels.