Electrical power is supplied by a 100 square foot array of photo voltaic cells. The south-facing roof overhang controls direct sunlight, by shading it in the summer and allowing it to provide passive solar heating in the winter. The passive solar heat gain is designed to heat the home for three consecutive cloudy days without relying on the auxiliary, in-slab radiant heating. Large cisterns are located around the home to store snow-melt and rainwater for potable water use during dry months. Grey water effluent from the on-site septic system is used for irrigation and to flush toilets.