Because most forced-air heating systems rely upon gas, architect Cass Calder Smith’s office consulted with Sun Light & Power in Berkeley, who provide energy-efficient design and building solutions, to find a suitable alternative. “In a mild climate such as California, it’s incredibly expensive to have a complete solar space heating system—–and it’s a storage nightmare,” says Gary Gerber, the company’s president. “The grid-tied photovoltaic approach cleverly solves the storage problem, and it’s really efficient when coupled with the right system.” At his suggestion, Smith and project architect Dera-Jill Lamontagne went with a high-efficiency, split-system heat pump designed for residential use.
All split-system heat pumps consist of two components. The heat pump, which looks like an air-conditioning unit, sits outside and extracts heat from the cold air using a compressor and refrigerant. The internal air handler then pumps the warmth throughout
the ductwork. Come summer, the whole thing works in reverse, exactly like an air conditioner (the SEER rating is 13).
Through the magic of net metering, gridtied houses with photovoltaic panels offer the best of both worlds—–essentially turning homeowners into energy brokers who can swap electricity for retail credits (but still enjoy heat on demand). Like something out of Alice in Wonderland, the meter spins both forwards and backwards, with excess electricity banked for future credit.
Says Gerber, “Clearly, solar isn’t the only way to go. We are driven by the concept that you can actually get to zero use of fossil fuels, and this approach is one way to get there.”