The Willow School is an independent elementary school located on a large wooded campus in Gladstone, New Jersey. Farewell Architects of Princeton, New Jersey, designers of the existing classroom building on the campus, is currently designing a new wellness center for the school to house classrooms, a cafeteria/multi-purpose space and teaching kitchens. This net zero building is targeted to be both LEED Platinum certified and meet the Living Building Challenge set by the Living Building Institute. Living Building certification requires several highly rigorous environmental standards including net zero energy and water consumption.

The owner hired Maclay Architects as a net zero envelope architect to work alongside and provide feedback to the architect of record. Working directly for the owner, we were able to effectively direct the design of the envelope, while also providing input on energy reduction strategies and balancing of energy. We provided feedback on kitchen equipment and refrigeration, daylighting, mechanical systems and structural design. This work required pre-design services to develop metrics for the team to target. Energy intensity(EUI) for the project is projected to be 19.7 kBtu/sf-yr for heating and cooling, with an additional 11.1 kBtu/sf-yr in process loads dominated by the commercial kitchen equipment and ventilation. From schematic design through construction documentation, we held regular coordination meetings with the architect and owner to review the design and identify decisions and strategies which would guarantee that the building to achieve the aggressive EUI. In addition, we coordinated with the architect’s major consultants, including the mechanical engineer, the structural engineer and the energy consultant to bring to light concerns across the disciplines and maximize efficiency by reducing loads.

Envelope details provided by Maclay Architects, which include walls, roofs, windows and doors, pay close attention to thermal performance, durability and water and air infiltration.  The envelope design meets net zero standards with R-20 below grade insulation, R-40 walls, an R-60 roof, R-5 triple-glazed windows and an air sealing requirement of 0.07 cfm50/sf. Specification of healthy materials will ensure high indoor air quality.

Construction is set to begin later this summer, and the building, as modeled, is very close to achieving some aggressive targets including near daylight autonomy, net-zero energy performance and compliance with the LBC red list.