Solar building design has been used since ancient times. In the more recent past, it has been more or less ignored as impractical, complicated, or too expensive. Incorporating the sun’s energy into the design of the built environment, however, is practical, simple, and affordable. Ancient civilizations knew that orientation to the sun was an important factor in the layout of their cities and homes. As the knowledge and technology of using solar, wind, and water sources evolves, owner-builders and building professionals alike will have a greater opportunity to incorporate energy-conserving strategies into any project. Thermal mass within a building regulates interior temperatures. The mass absorbs heat on sunny days and prevents overheating. At night, the stored heat is radiated into the building. The thermal mass at Caspar Point consists of 100 yards of structural concrete. The insulating envelope extends to below grade on exterior walls to integrate the foundation’s structural function with its ability to store heat. At Caspar the slab is insulated from the earth with R-11 insulation, the exterior walls are wrapped with R-19 insulation, and R-30 was used in the ceilings to create an insulating envelope