Since it opened in 2007, the Garthwaite Center in Weston, Massachusetts, has proved wildly popular—more so than its architects or school administrators ever predicted. It is constantly in use, year-round, for art shows, parent meetings, academic conferences, and community meetings. The building, part of the Cambridge School of Weston, was designed to accommodate faculty meetings and art and science classes that would take place during regular school hours.
Even so, the building, with a net energy use intensity (EUI) of 23kbtu/square foot per year, is performing ahead of its modeled EUI of 27, despite the fact that, in its first full year of operation, the EUI reached 40. After some fine-tuning and the installation of its rooftop solar array, the school was able to bring down its energy use.
Built into a hill, the two-story building houses laboratory classrooms, faculty offices, galleries, a science atrium, and a campus server room. Daylight filters in abundantly through a clerestory and a double-height glass wall. The design firm Architerra employed a number of sustainable elements, including radiant floors, triple-glazed windows, a composting toilet system, occupancy sensors, and zoned lighting controls.
The high school's commitment to environmental stewardship and its ongoing mission to make the Garthwaite a critical part of its educational curriculum have helped ensure the building's strong energy performance. Driven by a comprehensive pedagogical program, the building is designed to teach students about topics such as daylighting and energy use. "There is a great marriage between the building and the philosophy of the school," says Dan Arons, Architerra cofounder.
The school appointed teacher Marilyn Del Donno to the role of sustainability coordinator in 2010. She has been tracking the center's energy use and has implemented a number of changes. Temperature control proved to be a challenge at first, and it took time for the facility staff to establish the appropriate settings for hours of low and peak occupancy. While most of the center does not require mechanical cooling, the server room and two art galleries are air-conditioned. Del Donno discovered that the server room was responsible for roughly 50 percent of the building's electricity consumption, so, in the last few years, the technology director has combined servers to save energy. Initially postponed due to cost, a 70.1kW photovoltaic system was installed on the building's solar-ready roof in 2012. It now meets about 48 percent of the center's actual electricity demand.
Some features, however, have not been as successful. The original biomass boiler, which was intended to provide 80 percent of the building's heating from recycled-wood pellets, hasn't been used for several years because of operating problems. The school has been relying on its natural gas system.
Even though the project has demonstrated high energy performance, Architerra is recommending third-party retro-commissioning, now that they "have some data and experience with the building, to tune it up again," says Ellen Watts, Architerra cofounder. The firm has outlined goals, including reintroducing use of the wood-pellet boiler, checking on the ventilation and heat-recovery units, and further refining the temperature set points.
Del Donno insists that substantial change will come from educating the center's occupants on sustainability, which she often does during student orientation and visitor tours: "No matter how many systems you put in the building, the most important thing is a person's behavior."