The 1100 square foot Kumar Residence was in need of an addition and remodel to update the look and provide a fourth bedroom and space for living and entertaining. Now at 3,000 square feet, the 1950’s era ranch home that is located in a suburban cul de sac in the hills of Belmont, California is a modern, contemporary residence with European sensibilities and sustainable features.


A panoramic, true color view of the San Francisco Bay is facilitated by energy-efficient windows with high visual transmittance glazing (80%). Double pane high-performance European IGUs provide natural daylighting, thermal insulation from heat loss and excessive solar gain, and acoustic protection.

Pre-weathered zinc panels on the facade wraps around the entire building and clads the roof. Additional sustainability measures include spray foam insulation, high thermal mass, and natural ventilation to contribute to a lack of necessity for an air conditioning unit.

The Kumar Residence renovation was one in a series of buildings on which the Zeitgeist Design studio worked while building trust in the Passive House performance system. Founder Florian Speier says that the Colorado and San Francisco-based firm is now exclusively taking commissions for Passive House certification.

“But much more convincing than energy forecasts or indoor-outdoor living is construction quality and the durability of higher-quality construction,” said Speier. “Also, in this case, we can specify a twenty-foot-wide door that the Kumars can use easily even when they’re eighty years old. And we get about three times the energy performance of a typical locally built slider. That way it was win-win.”

The current Zeitgeist Design project that is breaking ground is a 5,000 square foot home in Steamboat Springs, Colorado.