Abstract: A solar heating system comprising a heat collecting-storage chamber at the upper level of a building; a solar heat collecting apparatus disposed and extending laterally within the chamber; a hot air supply and return plenum including a generally vertically extending central air supply duct and a plurality of generally vertically extending return air passages surrounding the supply duct; heat storage and yielding members disposed in the chamber and surrounding the hot air supply and return plenum; and mechanism effecting circulation of air through the system by drawing hot air from the chamber through the supply duct and by returning relatively cooler air to the chamber through the return air passages; wherein the heat collecting-storage chamber includes windows and a floor enclosing the chamber; the windows being above the heat collecting apparatus to enable impingement of the sun's rays upon the heat collecting apparatus; the floor supporting the heat storage and yielding members within the chamber; and the