David Baker Architects | Location: Silicon Valley
This sustainable building addresses the pressing need for affordable housing in Silicon Valley, one of the nation’s most expensive markets. The vibrant new community provides 66 affordable rental homes for low-income families—including homes reserved for homeless and at-risk families—in Sunnyvale, and it among the first zero net energy-ready, all-electric affordable housing projects in the state.
This challenging site exemplifies the interstitial urban space often available to affordable housing—in this case both isolated from and exposed to an adjacent freeway. The design aimed to mitigate the proximity to the freeway, address noise and air-quality concerns and provide places of refuge by placing the homes away from the front of the building and clustering them around planted courtyards and private patios.
Throughout the design, the team actively balanced prioritizing energy-efficient, passive design with the realities of controlling cost in a daunting construction market. These goals converged in a commitment to achieve the first all-electric affordable housing development for both architect and owner, including the first installation in the state of a central heat pump hot water system employing Sanden heat pumps, which have a high coefficient of performance and utilize CO2 refrigerant. This system combined with careful detailing and efficient heating, cooling, appliances and lighting, the gross energy use intensity was modeled to be only 15 kbtu/sf-year, and has proven to perform very close to that prediction in its first year.
A 114 kW PV array covers 46% of the building’s total loads, and 100% of common loads, dropping the impact of the building even further. With local residents opted-into a 100% renewable community choice utility, the project may considered among the first affordable housing projects to boast zero net annual operating emissions. Homes feature residential energy education monitors, devices that give real-time feedback on energy usage.
The site is situated within 1 mile from the southern tip of the San Francisco Bay, a vast tidal marsh where three watersheds converge. The surrounding areas have been heavily developed, including expansive industrial parks between the project site and the baylands, a naval air base, wide roadways, and expansive residential developments. Within a mile of the site, however, daylit creeks and greenways do provide some trace of the natural hydrology. As possible, the landscaping repairs the contemporary disruption of the watershed with native and drought-tolerant plantings, and improves the perviousness of the site and storm-water management with at-grade plantings and a permeable entry plaza and central courtyard. A pair of native seasonal grass berms calm the entry plaza, providing a buffered transition between streetscape and building entry, while capturing and retaining stormwater before returning it to the aquifer. Oak trees line the street frontage. Each home is allotted a private planter so that residents are able to tend their own gardens. Flowering plants and vines are planted throughout the site to support pollinators and insects in the heavily trafficked urban site.