Rimrock Passive House
A partially-buried concrete pedestal anchors the seemingly simple rectangular form to a sloped site overlooking Boise’s east end neighborhood. Conceived from the onset as a highly energy-efficient home that would meet the stringent Passive House standard, the competing concepts of openness and protection manifested themselves in the cantilevered form. A connection to the exterior and the expansive views to the south was a prerequisite. But protection from the hot summer sun and a desired sense of intimacy pushed back. The balcony at once serves as a shading device for the windows below and an overlook, providing airy views of the public trails crisscrossing the open range land below. The roof cantilevers to both the south and the east, forming an enclosure that simultaneously protects the occupants from the elements and enhances the existing connection to the surrounding canopy of trees.
The upper floor, directly accessible from the street level above, contains the kitchen, dining, living and master suite. Large sliding doors connect the kitchen and dining area to an elevated outdoor living space. A staircase leads down to two additional bedrooms, a media room and garage, all of which offer direct access to the yard and an on-grade patio.
A robust, high-performance thermal envelope ensures comfort and energy efficiency. On the first level the structural concrete walls were pushed to the exterior. A continuous layer of insulation fully separates these walls and floor slab from the spaces within. Above, a structural wood-framed wall is clothed in a thick layer of cellulose insulation contained in an I-joist cavity. Open-web floor and roof trusses allow for uninterrupted interior spaces and ample room for insulation. Superior indoor air quality will be assured by a balanced ventilation system. 100% of on-site energy use will be offset on an annual basis by a roof-mounted photovoltaic system.