Green Gulch Farm Student Housing — Passive House
Green Gulch Farm, located in Marin County, is a Buddhist practice center and a working farm. Taking care of the Gland and creating a sustainable community have been guiding principles, and the new Student Housing embodies
those concerns by combining several tactics to create housing with “near net zero” energy use.
The building was the first multi-unit project in the United States built to passive house standards. The two-story building is organized into four pairs of rooms that share accessible baths and kitchenettes. Each room has access to its own outdoor patio or balcony overlooking the farm valley. The combination of careful siting, use of super-insulation, tripleglazed doors and windows, airtight construction, and a heat-recovery system make for a building that does not require conventional heating and cooling. Besides lighting, appliances, and people, the only supplemental heat sources are electric towel warmers and inline gas duct heaters for the very coldest days.
The climate at Green Gulch is generally cool and foggy, so the structure is oriented for maximum solar gain. Triple-glazed windows (R-values of 5.0 and 5.26) are located for maximum daylighting and to balance interior light. Window frames are fiberglass, for reduced conductivity and increased longevity, and the glazing has low-E coatings tuned to orientation. Thermal bridging was avoided by careful detailing. Air infiltration was diminished by sealing and taping plywood joints, using air-tight electrical outlet boxes, applying an air barrier below the bottom truss chord, and gasketing all openings into the attic. Insulation far exceeds California standards.
Exterior materials were chosen for longevity, like the standing-seam metal roof, which also facilitates water-catchment to a 5,000 gallon tank, providing water for about 70% of toilet use. In the future, a grey-water system will be added, for which the building is pre-plumbed.
• Structural Engineer: Komendant Engineering
• Landscape Architect: Chuck McCulloch
• Passive House Consultant: Essential Habitat
• Mechanical Engineer: Meline Engineering
• Photography: Adrian Schulz Architekturfotografie