The 21-acre site in the town of Cumberland was purchased two years ago, and ground was broken officially this past August. Though the building committee settled early on a superinsulated envelope for the school, passivhaus certification wasn't always part of the plan. Several factors conspired to help encourage the building committee to seek certification, however.
Naomi Beal, chair of the building committee, is also director of PassivhausMAINE, and had spent a year long sabbatical in Germany, where passivhause designs are far more common. An early decision to change architects brought Kaplan Thompson Architects of Portland to the project, a firm well-versed in high efficiency passivhaus designs. According to the school's head, Jenny Rowe, the school's mission informed the decision as well.
"We knew we wanted to be as responsible as we could to the earth," she said.
"As Friends, as Quakers, we really try to walk the talk. If one of the things we talk about with our students is taking care of the earth and being responsible stewards of it, then it makes sense to try to think of the most energy-efficient building we can."
Rowe also noted that passivhaus standards will benefit the school in several ways, particularly economically.
"For us to know that in every single year ahead of us we will have no energy costs, that's pretty amazing for a small school where three kids difference in enrollment can make or break a budget," Rowe said.
"Having a predictable budget is very helpful."
The project has been met with strong enthusiasm from all involved, particularly those that haven't worked on a fully passivhaus certified building before. The school's builders, Warren Construction Group, are familiar with high performance buildings, but had never handled a passivhaus project before starting construction on the school.
Due to the building's intended use, ventilation is a key concern, and to that end the architects chose to employ a RenewAire energy-recovery ventilator. Though it operates well below the efficiency of certified passivhaus equipment, the builders noted that it was the best available choice.
The architects also chose windows with a high solar heat gain coefficient, while bulking up on window and sub-foundation insulation. Heating and cooling are provided by Daikin minisplit air-source heat pumps, and water is heated by an on-demand electric resistance system. With Schuco ADS aluminum doors that have the same energy performance rating as the windows, and an air-tightness goal of 0.5 air changes per hour at a pressure difference of 50 pascals, the building is set to just make the standards for passivhaus certification.