If you were to peek in the basement of 125 Haus, you might notice the conspicuous absence of a furnace. Upon closer inspection, the triple-pane windows, on-demand gas hot water heater, and heat-recovery ventilator may—if green building practices are your thing—grab your attention as well. And then there’s the direct-vented fireplace and walls that are more than a foot thick. But if this home’s over-the-top energy efficiencies don’t make an impression on you, its bright, modern, and serenely cozy mountain style certainly will.
125 Haus is the brainchild of international architect Jörg Rügemer, an associate professor at the University of Utah’s College of Planning + Architecture. After arriving in Utah from Cologne, Germany, in 2006 to teach sustainable design and theory, Rügemer decided to design and build a home for him and his family as a research project. Germany is known for modern and high-performance architecture and has building standards—called Passivhaus—that are 50 to 60 percent more efficient than US practices. “I wanted to find out if it is possible to adapt the Passivhaus standard to the predominant construction methods in Utah,” he says. Because of its similarities to the mountains in his native Europe—as well as its challenging 7,000-feet-above-sea-level elevation—Park City’s Summit Park neighborhood became Rügemer’s choice location to test this theory: is it possible to build a market-rate home—on the cutting edge both in terms of aesthetics and energy efficiency—in one of Utah’s harshest climate zones?
Rügemer began by designing the house specifically for its location and exposure, tweaking every detail to optimize sunlight and mountain aspect. Architectural design details incorporate 15-inch-thick insulation, airtight closures, minimal exterior surface, and windows precisely oriented to capture as much of the sun’s heat as possible, beaming it down to floors with reverse radiant heating. A heat-recovery ventilator brings fresh air in and turns stale air out. Even heat from the cars in the garage is captured and transferred to the main level, and snow on the flat, reinforced roof acts as a thermal blanket.
Another vital component of the project was close collaboration with the contractor and building officials. “We critically questioned each component, assembly method, and material,” Rugemer says. County planners had to be convinced that the house would perform without a conventional heating system. After all, it’s not every day they see a plan with no furnace.
This home’s extreme efficiency, however, in no way detracts from its beauty. Simple, elegant, and compact, its design is refreshing and distinctive in a mountain setting. The stucco and cedar exterior is punctuated with a playful assortment of windows, some with metal eyelash shades that shield the summer sun. The home encompasses three light-filled levels: a garage and large studio on the lower level; the kitchen, dining, and living rooms on the main level; and three bedrooms upstairs.
The house is divided in half by an open staircase to circulate light and perform as a thermal chimney. The south-facing front patio becomes a sunny outdoor gathering place during the winter, and a small deck off the kitchen is perfect for year-round grilling.
A primarily white color palette, punctuated by pops of color, and minimalist interior design are enriched by the sensory qualities of the beautiful surfaces. In the classic Euro-kitchen, counters the color of gunmetal are made from recycled paper. High-performance stainless steel appliances, sleek white laminate cabinets, and pale gray Italian floor tiles absorb heat and redistribute it to the studio below.
Naturally stained red birch flooring and deep window openings create an artistic juxtaposition in the main living room.
Unusually long and low horizontal windows frame sweeping forest views, even from the couches. The furnishings are spare and sculptural, and nearly every room is accessorized with beautiful stones, some from a Swiss village where the Rhine River originates, reminders of places meaningful to the family who lives here.
The combination of clean visual design, massively thick walls, and a silence uninterrupted by mechanical systems creates a peaceful and enveloping interior environment. Rügemer says the house has become his family’s “physical and emotional retreat from the overload of the world.”
The results of 125 Haus’s innovative design are in the numbers. The average cost of heating and cooling the 2,400-square-foot house is less than $25 a month—80 percent more efficient than the to-code houses surrounding it. 125 Haus been frequently recognized as Utah’s most energy-efficient and cost-effective single-family dwelling, is the recipient of numerous state and national awards, and has become a model for architects and builders both here in Utah and across the country. All for a building cost that fell well under $200 a square foot.
“Green” and “eco-friendly” may seem like the latest buzzwords in home design, but neither is a new concept. Rügemer reminds us that for hundreds of years European farmers lived in “housebarns” with hay stacked in the attic and the warmth of the livestock rising from the ground floor below. 125 Haus’s state-of-the-art energy efficiencies reap big rewards based on these simple principles, and do so in a way that proves green living, affordability, and high style can indeed coexist.