Passive solar heating and shading, as well as the building's thermal mass, reduce the energy required for space conditioning. The utility grid functions as a backup power source, kicking in only when battery voltage is low. The PV system powers compact fluorescent lights and computers for the 10-person office. In addition, the Brandborg's power their home with a 1.4-kWp array.
Domestic water is heated by a solar-thermal water heater.