At just 712 square feet of living space over a 430 square foot workshop, every square inch of the tall thin structure has been optimized for flexibility and efficiency. A whopping 3 kW photovoltaic solar array, custom fabricated by Henry DeFauw, cantilevers off the narrow roof structure and serves as a rain screen for the exterior metal side stair below.
David Baker‘s Zero Cottage is LEED for Homes Platinum certified and is the first Passive House certified residence in San Francisco. The project is also on track to achieve Net-Zero Energy certification through the Living Building Challenge, after the first year of energy performance can be monitored.
Photo by Piper Kujac
Because the residence is part of the architect’s own home, Baker was able to experiment in ways he may not be able to with other clients. The custom exterior cladding is made from scrap metal pieces and prototype clips fabricated in the on-site workshop. Intermittent planter box panels provide a playful functionality and can be relocated to other panel locations as the seasons and sunlight angles change.
Contrary to the name, the home’s Passive House construction combines a robust (even aggressive) combination of exterior wall membrane layering, including continuous exterior foam insulation and triple-glazed windows. The goal is to capture heat generated from day-to-day use (by people, appliances, and computers) and use this heat to warm fresh air ventilated into the home. Likewise, the tight building envelope minimizes exterior heat gain on warmer days. With a 92% efficient heat-recovery ventilating (HRV) system, and an air-change-per-hour rating of 0.5, the house does not need conventional heating.