Elk Ridge Passive House
A showcase of energy efficiency in a life among the treetops
Russ and Krista Hellem, owners of a high-performance window company, were searching for an architect to design their family home that also exemplifies a high standard of energy efficiency and showcases their window technology. Among the goals for their home was that it meet the Passive House building standard—a stringent set of guidelines that maximize energy efficiency through passive measures like building orientation and increased insulation while utilizing solar radiation and natural ventilation to heat and cool the home as much as possible. The opportunity for us to push sustainable strategies to the limit in developing the first Passive House in Montana was an invaluable opportunity.
Set into the hillside outside of Missoula, Montana, the house is oriented to optimize the solar exposure, using the low winter sun’s energy passing through the windows to warm the home. The home navigates the steep terrain of the site by carving out part of the hill and using the earth to insulate the bedrooms and office space on the lower level. The upper level includes the open public spaces of the home and is wrapped in a ribbon of glass that offers views out to the mountain ridge below.
Super-insulated concrete walls wrap around the other side, with small windows punching through the walls to bring daylight into the lower level. The concrete texture is inspired by the vertical grain of wood found throughout the surrounding pine forest. Locally-reclaimed Douglas Fir, warm in contrast to the concrete below, lines the deep overhangs that shade the windows during the summer to reduce the solar heat gain and glare. A standing seam roof of weathered steel blends into the forest, its color becoming richer with each passing winter.
The systems within the home—including the mechanical system designed by the owner—support the passive strategies embedded in the design and reduce the project’s carbon footprint. A continuous layer of insulation wraps and seals the exterior envelope behind the exposed surfaces of the walls and roof to reduce the energy needed to temper the interior. Triple-pane, engineered windows and doors are located to optimize the climate response in summer and winter. A ground-source heat pump—a cooling and heating system that uses the earth to transfer heat—supplements the building’s passive strategies to maintain a comfortable temperature year round. Combined with the thoughtful composition of the architecture, the home becomes a model for sustainable living.