This Design Certified PHIUS CORE Passive House sits in Twin Lakes, Colorado, shaped by clients who arrived with a seemingly straightforward goal: a mountain chalet, certified to Passive House standards and buried almost completely into the topography. The project felt like a natural fit for our studio, and it quickly grew into an extremely rewarding challenge. Working with thoughtful structural engineering, energy modelers, and mechanical gurus, we used the natural slope of the land to berm the lower two levels into the hillside while still opening the home toward sweeping views of the Twin Lakes.
Morgan Law
Sarah Vanderpool
Kip Construction
Northeast Projects, LLC
Lopez Smolens Associates
Bright Sense
John Reuter: Greenworks
CTL Thompson
2,334 sf
Twin Lakes, CO
The lowest level holds the entry, mudroom, and garage. This space is almost entirely beneath 20 feet of earth, open only on one side to provide access. Private sleeping areas rest on the middle floor, and the top level opens to the double-height living, kitchen and dining spaces. A large open stair and a pneumatic elevator connect all three floors. Inspired by the original chalet image, we used wood glulam beams to support a thin roofline that lightly shelters the larger program beneath it. Two upper decks extend the interior outward and frame the surrounding landscape. Large triple-pane windows provide expansive views in the east and south directions, while specialized glazing treatments help block excess heat.
Every detail was carefully studied to create clean interiors and ensure that the Passive House model performed as intended. Through many rounds of adjusting insulation values and demonstrating airtightness, the project earned its Passive House design designation in November 2025. It is also the first passive house to use only instantaneous water heaters at each fixture, rather than a tanked system, while still meeting the Energy Star certification prerequisite. Supported by solar panels, an Arctic Heat Pump, and a Brink ERV, this home is prepared for a changing climate and gives its owners a place to age in comfort while proving that thoughtful design can make sustainability accessible.
