Abstract: An apparatus which is in one embodiment structurally integrated with a building and has a solar collector plate with a front side and back side. The collector is mounted a spaced distance from an insulated building interior wall to form a preheating channel with one of its sides. Roof mounted solar admitting panels are mounted spaced from the other side of the collector to form a second or primary heating channel. A collection chamber is in circulating air communication with both channels and allows air to pass from the preheating channel to the primary heating channel. During heating air passes through preheating channels and primary heating channels and flows to a storage unit carried beneath the structure or cycled to the building structure. A valve to the ambient environment allows air to flow into the storage unit. When the storage unit is cooled by introduction of circulating air through a valve joining the apparatus with the building environment.