This is a big and comfortable house that requires very little energy beyond what it produces itself!

PASSIVE SOLAR DESIGN with 3 components:
1. Letting the sunlight in / keeping the sunlight out: At approximately 40 degrees North Latitude, the southern orientation and proper overhangs make this easy.
2. The "envelope": R-25 walls and R-40 ceilings of Structural Insulated Panels (SIP), with supplemental fiberglass insulation and Triple-glazed windows make this a VERY "tight" house. SIPs are made of recycled materials.
3. Thermal Mass: With 16,000 gallons of water in the Indoor Lap-Pool and lots of concrete on the Lower Level and with hydronic heating in the slate/tile floors above, this house has plenty of mass to retain its warmth in winter and its cool in summer.


ENERGY PRODUCTION:
1. Electricity: The 9 kw photovoltaic array is part of the slate roofing system. Through its PG&E Time-of-Use meter, the house "sells" energy back to the Utility Grid at Peak Rates (between noon and 6 PM) and consumes energy mostly at Off-Peak Rates. For the privilege of being connected to the utility grid and treating it as a very deep supplemental "battery bank" by trading energy in this way, the Pacific Gas & Electric Company (PG&E) bill is less than $6/month!
2. Heat Energy: 18 Roof-Top Solar Hot Water Panels drain back into a 350-gallon tank. From this tank, all heating needs can be served: interior space heating through the hydronic system in the floors; domestic water heating mostly through the thermo-siphon effect; the swimming pool and the spa through heat exchangers built into the tank. If the sun does not shine, an outdoor wood-burning stove with its own 170-gallon water jacket exchanges heat into the larger tank in the house to serve all heating needs. No sun? No wood in the outdoor stove? Propane from the twin 1000-gallon tanks (owned) backs it all up!