Architect Sarah Nettleton, AIA, LEED AP, believes in the simple approach to life and to solving problems. In her view, whiz-bang technology is no substitute for common-sense techniques that promote energy efficiency. This is why the principal of Sarah Nettleton Architects first explores tried-and-true sustainable solutions that often are free but always effective. “Simple can be sustainable,” she says.
Nettleton applied this line of thinking as her firm designed this LEED Gold custom home overlooking the Minnesota River Valley in St. Peter. The clients had read Nettleton’s book, The Simple Home: The Luxury of Enough (Taunton Press), and wanted a modern farmhouse that incorporated some of her design concepts and sustainable strategies. Rather than relying on pricey mechanical equipment, the architect used the land and orientation to optimize natural daylight and ventilation.
Nettleton started with a narrow, bar-shaped plan that allows windows on three sides of most rooms, as well as a screened porch at one end. She oriented the 2,900-square-foot house so that the south side promotes passive solar gain, and she used computer modeling to track the sun so the client would have a bright, warm place to sit at all times. “The windows on that side feature glass with high solar heat gain,” she says, which is an important part of the passive system. As her firm explains, “Like traditional adobe buildings, the walls and floors can heat up during the day and then release heat throughout cooler nights.”
The home had to be highly insulated and tight to combat the harsh Minnesota winters, so Nettleton chose structural insulated roof and walls, and specified a foundation system that features insulation in between layers of concrete—sort of like an ice cream sandwich. An underground air-to-air system with an energy recovery ventilator brings fresh air into the home.
In addition to passive systems such as exterior sunshades that reduce heat load, Nettleton also used an active solar thermal array that provides 11 percent of the home’s heating load. A zoned, in-floor radiant system offers additional heat in the coldest winter months.
The home boasts de rigueur green products such as windows with low U-factor ratings; energy-efficient appliances and boiler; and low-flow fixtures. A rainwater catchment system collects 59 percent of the water from the roof and directs it to a cistern for irrigation.
One of Nettleton’s top goals was to secure third-party certification that the house performed as intended. “We are all aware of LEED buildings that under-perform or perform below code,” she says, “so we checked to make sure we got it right.” As proof of the firm’s efforts, Nettleton proudly reports that the home is 75 percent more efficient than the International Building Code.