Abstract: A combination multi-story greenhouse and structure in which the sun's rays are utilized to heat water which is thereafter stored to be circulated when needed throughout the structure is disclosed. Indirect heat exchange to maximize use of heat values is also employed. The greenhouse has a first upper roof and side structure designed to best capture the angle of the sun's rays and a second lower roof adapted to receive and transfer heated water. The sun's rays are utilized to enable the growth of plants and in this capacity may be utilized even near the bottom of the greenhouse by use of reflecting means. Heat coincident with the passage of the sun's rays is transferred into water by means of spraying water from nozzles on the underside of the upper roof of the greenhouse and collecting the water on the top of the bottom roof of the greenhouse. Heated water thus collected is circulated into the basement through a heat sink and into a water storage area.