Seattle Green Building Slam Video, Island Passive House!

This prefabricated 1,800 square foot Certified Passive House is located in the rugged central highlands of Shaw Island, in the San Juan Islands. It is the first Certified Passive House in the San Juans, and the fourth in Washington State. The home was built for $330 per square foot, while construction costs for residential projects in the San Juan market often exceed $600 per square foot. Passive House measures did not increase this projects’ cost of construction.

Passive House performance is achieved through careful design, modeling and construction that is site and context specific, not the addition of expensive “green” mechanical or photovoltaic systems. The occupants’ total energy use currently achieves the 80% reduction in primary energy use required by the 2030 Challenge in 2025, without the addition

of on-site energy generation. The air-sealed exterior shell has over twice the insulation, and windows and doors are three times more efficient than required by code. Detailing that eliminates thermal bridges, and a heat recovery ventilator further reduce the home’s heating load and creates superb indoor air quality. Small hydronic radiators provide the modest amount of supplemental heat required in the winter. Careful solar orientation and window placement, and hidden exterior operable shades, keep the house from overheating in the summer. The home was largely prefabricated in a Washington facility that was originally intended to be a nuclear power plant. The exterior walls were installed as completed panels. The kitchen, two bathrooms, and most of the mechanicals of the home were pre-constructed as a central “pod” and craned into place on site. The home was “weathered in” 17 days after the start of construction. The clients are retired teachers, and desired a low-maintenance, cost-effective, energy-efficient house in which theycould age in place; a restful shelter from clutter, stress and overstimulation. The circular floor plan centers on the prefabricated pod. Radiating from the pod, cabinetry and a minimum of walls defines functions, with a series of sliding and concealable doors providing flexible privacy to the peripheral spaces. The interior palette consists of wind fallen light

maple floors, locally made FSC certified cabinets, stainless steel hardware and neutral tiles in black, gray and white. The exterior materials are painted concrete fiberboard lap siding, Ipe wood slats and galvanized metal. The home is situated in its natural environment with no formal landscaping.