Booth Hansen’s award-winning Solar House is a sustainable dream

The homeowners purchased an existing home on a triangular corner lot in their desired neighborhood. The home, however, didn’t quite suit their needs. To complicate the matter, setbacks would have allowed for almost no buildable space. Luckily, Booth Hansen had an innovative solution. By creating a design that reused the existing foundation, along with the northern and western walls, they were able to overcome the zoning restrictions while also aligning with the client’s sustainable ethos. “We didn’t want to have to tear everything up, pour a new foundation, and put up new CMU walls,” said Larry Booth, FAIA, Principal/Director. “A good wall is a good wall — let's save it.” By reusing what was salvageable from the old home, they were also able to maximize the lot’s 100-foot-wide by 100-foot-long dimensions.

As long-time Chicagoans, the homeowners had experienced the dark interiors that often characterize their city’s homes. That’s why it was important to them that their new home really let in the light and connected with the outdoors. To make this happen while working within the existing constraints, Booth Hansen divided the home into three staggered triangular volumes to maximize eastern and southern light and create pockets of outdoor space. Public rooms are concentrated in the center volume where 5-foot-wide-by-10-foot-tall, floor-to-ceiling E-Series windows dominate the double-height living room. The two flanking volumes continue the theme with floor-to-ceiling glass in the same proportions. Upstairs, the windows begin further from the floor and are two feet shorter to provide privacy in the bedrooms. Although the home is oriented toward the street, a 6-foot fence running along the front of the property also helps to preserve privacy.

The height of the windows helps maximize the passive solar heat gained during the winter, and low-emissivity coatings help boost the energy performance of the windows and doors. In this case, a combination of coatings was used, including Low-E4® and HeatLock® technology. Low-E4 helps keep conditioned air inside the home while HeatLock technology is specially designed to keep heat from escaping the interior in a northern climate — learn more about our Low-E coatings. 

And although the interior is truly flooded with natural light, there’s actually a 25% window-to-wall ratio because of the largely windowless walls that were reused on the northern and western sides. The home has 1.5 inches of continuous insulation and spray-foam in the cavity, helping the walls reach an R-Value of 34 — well beyond the R-Value of 24 required by code at the time of build. These high-performing walls help increase the efficiency of the HVAC systems, which include an air source heat pump, a heat pump water heater, and an energy recovery ventilator. Over 80% of the home’s power is generated by the south-oriented solar array hidden on the roof. The result of all these efforts is that the home not only exceeds local code but also has an Energy Use Intensity (EUI) of 3 — bringing it to nearly net zero, and much lower than the typical Chicago home, which might have an EUI of 49 if it meets baseline energy code. “We were extremely energy efficient, but we had to strike a balance between what would be comfortable for them and what would make the house beautiful,” said Booth.