"Basically, the home is three stories, with a three-level atrium or cylinder at the center," Oshatz explains. "The staircase wraps around and cantilevers out from the stone cylinder, which is also an elevator. The floors, which wind their way out from the central cylinder, were placed to take advantage of the lake views, how sunlight enters the home, and the curvatures reflecting the way you wind between the trees."

"When Robert asked us about textures and colors, we said we like natural materials in their original colors like stone and wood," the homeowners add. "He said he would work with our palette. To our eyes, he seemed to let the forms of the house dictate the materials." 

Adds Oshatz, "Every site has its own poetry. We wanted to relate the structure and the materials to the poetry of the site." They chose natural stone inside and out, interior soffits of hemlock (to help the interior remain light and airy), concrete floors stained an earthy rust color, and on the exterior stucco that highlights the edges of the floor planes and defines the upper floor volume, and cedar fascia.

Siting for Sun and Shade  

How do you heat and cool a 7500-square-foot house with so much glass? First, Oshtaz specified Heat Mirror glass, which is similar to triple glazing "and is Low-E, argon-filled, and has a U value," he says. Siting the home was also a factor.

"One problem we had in terms of glass is that the major view is to the lake, which is north," he explains, "so I sited the kitchen on the east side so it would get sunlight in the morning at a low angle. On the south side, which is at the back of the house, we put glass protected by large overhangs that shade the house in the summer. On the west, the glass provides views of the lake looking northwest, which is shaded by trees in the summer. In the winter, we have the west sun coming in in the afternoon, and in the summer, deciduous trees block the sun."

More glass also could have meant higher energy loss and less room for ductwork. But the team found the perfect solution. 

Electric Zoning Systems and Geothermal  

The team selected Mitsubishi VRF zoning systems. The company engineered this system to respond to inverter-driven technology and state-of-the-art heat recovery by responding to minute-by-minute changes in cooling and heating requirements or load. By varying the refrigerant flow to individual zones, the family could enjoy cooling and heating as necessary in a house designed to bring the outdoors in.

The homeowners control the system remotely using their smartphones. The system is also whisper-quiet. "From the beginning, one of our requirements was a quiet system," they say. 

The team paired the water-source heat pumps with a GeoExchange vertical closed-loop geothermal field for cooling and heating. The geothermal vertical closed-loop system uses the ground as a heat sink, as soil temperatures remain relatively constant at 55 degrees Fahrenheit. The system's compressor raises that temperature to a usable range in the winter, and the underground heat is pumped indoors. In summer, the process is reversed, with indoor heat pumped underground. 

Why geothermal? "We analyzed the site with the State of Wisconsin and considered solar and wind power," Oshatz says. "At the time, the State was recommending against wind power in this area. They suggested that, because of the trees, solar wouldn't work either. As we designed and built the home, we realized solar would work in the future. We wired the house for solar, which the clients may add to the geothermal in the future. For them, geothermal was the most environmentally sensitive solution and the most respectful to the site."