Abstract: A portable, lightweight solar panel for mounting against window panes which incorporates an array of absorbers, diffusers and flow directors, reflectors, heat storage elements and an automatic flow directing valve. The heat concentrators are corrugated elements located to reflect heat and light from contact with the reflective surface to collectors located in the unit. The collectors or heat storage elements are positioned in the troughs of the corrugated elements and the tubular elements are in stand off relation to receive the parabolic focusing projection of the sun's rays. These units act as heat supplement means for interior space.