the present invention in an energy conserving greenhouse involves an insulated and opaque structure whose inner walls are preferably formed , coated or colored to reflect visible light striking thereagainst onto plant surfaces therein , the structure utilizing a shuttered lense arrangement of minimum dimensions , that is open during daylight hours to pass sunlight from a focusing solar collector , that sunlight passing through an infra red trap to heat a material therein , that heat being removed for immediate heating of the structure and / or storage for later heating thereof , the remaining sunlight spectra , including the visible spectra passing therefrom and to a diffuser that directs and disperses it throughout the structure interior .