UC Davis has been leading the way in net-zero construction and energy research for years. Recognizing that homes and cars are responsible for just shy of half of carbon dioxide emissions in the United States, the project is a foray into how automobiles can factor into the efficiency equation. "UC Davis and the Davis community have launched some of the most innovative housing models in the country, from cooperative housing to solar villages to zero-net-energy at the neighborhood scale," says Bob Segar, UC Davis Assistant Vice Chancellor, Campus Planning and Community Resources. "The next entry is the Honda Smart Home—it's showing how the electric car can be managed as your house's biggest appliance." The house features a 9.5kW solar array, which produces direct current. The charger was adapted to accept power directly from the panels without any conversion loss.
Adele Chang and Mark Rohling of Pasadena firm Lim Chang Rohling & Associates designed the house, which is three times more water efficient than a typical house hold. The garden is xeriscaped and irrigated with graywater. The garden is also a source of energy for the residence. "We worked with the UC Davis Western Cooling Efficiency Center to design an experimental ground-source radiant heating and cooling system that captures thermal energy from eight boreholes in the garden," Koenig says. "This type of borehole has the promise of dramatically reducing the cost of geothermal HVAC systems in the future." This video explains the mechanics and "thermal heart" of the home.
The house uses about half as much energy as a conventional residence in the area. Over the course of a year, it is projected to produce 2.6 megawatt-hours of energy while a comparable home will consume 13.3 megawatt-hours. "This offsets nearly 13,100 pounds of CO2 annually," Koenig says. "Plus, it uses renewable electricity to power driving." To accomplish this level of energy savings, the architects designed a structure that would consume less. "We set out to build an extremely efficient envelope using passive design techniques, optimizing the house layout, windows, and insulation. Then we added extremely efficient heating, cooling and lighting systems, as well as appliances," Koenig says. "The passive design techniques resulted in an open space with tons of natural light. It’s a beautiful environment to spend time in." A Silva Giant LED floor lamp by Laguna Beach-based designers Cerno, Kristina sofa by Ekla Home, Loop coffee table by Arktura, area rug from Shaw, and end table from Iannone Design furnish the living room.
Sustainable materials feature prominently in the design. "We focused on using sustainable materials wherever possible," Koenig says. "The entire house is constructed with FSC-certified lumber. Concrete is very CO2 intensive, so we used volcanic ash to replace half the cement needed for the foundation slab. And rather than cover the slab with wood, we polished it to create a beautiful, durable finish."
The kitchen features polished-concrete floors, a Cambria countertop, and an Energy-Star rated refrigerator from Kitchen Aid. The cooktop, oven, and dishwasher are from Bosch. "With the exception of the experimental technologies, everything we’ve used is available off the shelf," Koenig says. "What really sets this project apart is that we’ve put all the pieces together. Everyone out there building a home should start with passive design and a well-insulated envelope."
Lighting throughout the house is exclusively solid-state LED and was developed to complement the body’s natural circadian rhythm. "This technology is also used on the international space station," Koenig says. "Blue-ish hues are emitted in the morning, and amber tones are emitted at night. Honda worked with researchers from the California Lighting Technology Center at UC Davis to explore the circadian color control logic."