A solar energy thermostatic controller using a solid-state microcomputer that manages air mover(s) to supply heated air for building space heating. Methods includes microcomputer software for communicating with temperature sensors located at the solar heating source, the supply vent source and the building room/interior. The present invention thermostatic control device features a data logger to record temperatures and humidity history, and elapsed time usage history of solar heated air available from attics and crawl spaces; or solar collectors mounted in or on walls, rooftops, or exterior locations. The thermostatic control device manages use of limited solar heated air for building environmental control. Program controlled temperature set points manage an HVAC blower to gather solar heated air during the daily sunlight solar excursion and to control shutdown of the supply system when solar heated air temperature falls below present room/interior temperature. Methods include permanent memory storage of historical data.