The Making of New York’s Greenest School

An education in building a sustainable urban future

P.S. 62 – The Kathleen Grimm School for Leadership and Sustainability at Sandy Ground. Photo © James Ewing | OTTO.

As soon as she saw the overgrown plot of land, nestled among the neat lawns and peaked roofs of two-story homes on the South Shore of Staten Island, Bruce Barrett had a vision of the future. The vice president for architecture and engineering at New York City’s School Construction Authority (SCA) recognized an opportunity to test an innovative concept that could change the way that public schools are made. “When I saw the assignment,” Barrett says, “I thought, ‘Wow, this is going to be our chance to build a net-zero school.’”

In September 2015, New York City’s most environmentally sustainable school opened its doors. Named the Kathleen Grimm School for Leadership and Sustainability at Sandy Ground, or P.S. 62, it is designed and built to meet an ambitious goal — ​net-zero energy — ​by generating as much energy each year as it consumes. It is the city’s first net-zero-energy school, and one of the first of its kind in the United States.

Aerial view of P.S. 62. Photo: Stark Video Inc. | Aerial NY © SOM.

At first glance, it’s apparent that P.S. 62 is not a typical academic building. The school’s cantilevered roof is covered in hundreds of photovoltaic (PV) panels, which convert solar energy into electricity. The sweeping solar array is only the most prominent feature among dozens that contribute to reaching the building’s net-zero goal. In addition to producing its own energy, the school is designed to consume 50 percent less energy than a typical New York City school. The PV panels require a lot of real estate — New York City’s most precious commodity — which is one reason why Barrett knew that the spacious Staten Island site was perfect. At the SCA, she manages the design and construction of new schools, as well as the maintenance and renovation of the city’s 1,600 existing facilities.

Buildings are the number one source of greenhouse gas emissions on the planet — and in New York City, public schools account for nearly 40 percent of emissions from municipal buildings. P.S. 62 shows a better way forward.

Tackling a Global Challenge

Barrett is keenly aware of the environmental impact of New York City’s public schools. P.S. 62 responds to the urgent challenge to reduce greenhouse gas emissions, a key component of the city’s OneNYC initiative to confront climate change. Buildings are the number one source of greenhouse gas emissions on the planet — and in New York City, public schools account for nearly 40 percent of emissions from municipal buildings. Intent on lowering this number, Barrett conceived P.S. 62 as a pilot project — ​a chance to test out a range of strategies that could improve the energy efficiency of schools throughout the five boroughs.

Barrett shared the idea with committees within her organization, and, gaining their support, went to pitch it at City Hall. “Everyone was enthusiastic about it,” she says. With the project’s funding still in flux, she organized a design competition to select the architect, and ultimately chose SOM for the job.

P.S 62 rear facade with cantilevered photovoltaic canopy. Photo © James Ewing | OTTO.

Breaking New Ground

SOM’s Education Lab, a studio within the firm, focuses on designing schools that respond to 21st-century challenges — not the least of which is the environmental impact of what we build. The group’s designs include high-profile projects such as the University Center at the New School, a 16-story academic building in Manhattan that earned a national award from the American Institute of Architects for its sustainable design. While this project is one of many progressive green buildings by SOM, designing a net-zero-energy school presented an altogether new challenge.

“When everybody gets in a room and says, ‘We have a singular goal — ​to save energy,’ it completely changes the equation.” — Chris McCready, SOM

Only a handful of net-zero-energy education facilities had been built in the United States, and none had been designed to meet the year-round demands of a New York City public school. “There were no good examples of how this is done, so we had to form teams of collaborators and create unique working processes to understand how to actually accomplish something like this,” says Roger Duffy, a design partner at SOM.

P.S. 62 play area with photovoltaic facade beyond. Photo © James Ewing | OTTO.

Photovoltaics harness our most abundant source of renewable energy — ​the sun — ​but the panels require space, and their cost is still significant. Due to the limited amount of power that could be economically generated on the site, the design team knew that in order to achieve net-zero, it should design a building that consumes as little energy as possible.

From the start, SOM called upon the unique expertise of all the consultants involved in the project, asking them to “think in a visionary way,” according to Chris McCready, a director at the firm. “Having a singular focus for the entire team is transformative,” he says. “People who wouldn’t normally be involved in the conversation started thinking of ways to save energy. For instance, the kitchen consultant came through on saving huge amounts of electricity. Many consultants had never been asked, ‘What could you do to bring down the energy consumption of this building?’ When everybody gets in a room and says, ‘We have a singular goal — ​to save energy,’ it completely changes the equation.”

The economics of net-zero seemed especially complex. SOM had designed many projects for universities and private academies, where more substantial budgets often underpinned the team’s design innovations. But the commission for P.S. 62, while certainly no less ambitious, would have to be achieved within the budgetary constraints of a municipal agency. “We realized that we couldn’t just throw a lot of money at it to reach net-zero,” McCready says. “We needed to come up with cost-effective ways of getting to our goal.”

The design team began by finding a new way to communicate. It created what Duffy calls a “feedback loop” — ​a rigorous process of assessing sustainable design features in terms of the value they would add to the project. “We could suggest efficiencies to the energy consumption of the building, and at the same time have the client understand what that investment might look like,” Duffy says. He speculates that this evaluative framework is one of the key factors that influenced the SCA’s choice of architect. “I think the SCA appreciated the combination of the pragmatic and the visionary, and that both of these qualities could coexist and be part of a shared equation.”

Aerial view of P.S. 62. Photo: Stark Video Inc. | Aerial NY © SOM.

The design team considered hundreds of possibilities to improve the building’s energy efficiency, and worked with the SCA to select the most appropriate and durable options. Through this process, features such as radiant heating were ruled out, while other high-value solutions became integral to the building’s design.

Let the Light In

McCready explains that some of the project’s most effective energy-saving features are based on passive design strategies, which involve careful decisions about the building’s shape and orientation on the site. By maximizing the natural light that reaches the building’s interior, the school’s dependence on electric lighting has been substantially reduced.

“We have more daylighting than in any school we’ve ever done. And because of the design of the interiors, it’s just mind-bogglingly beautiful.” — Bruce Barrett, SCA

To a great extent, the school’s design is therefore driven by daylight. Working closely with Rob Diemer, a sustainability consultant with the firm In Posse, the designers outlined the building’s fundamental characteristics. The team knew that the school needed to be just two or three stories high to allow natural light to reach the deepest parts of each floor, and that a large central courtyard would bring in additional daylight. The entire building was oriented slightly off the site’s north-south axis to capture the greatest amount of sunlight throughout the day. The team then considered how to organize the school’s various functions within the building.

“The collective group — SOM and In Posse — said, ‘Listen, the south-facing and the north-facing elevations are where it is easiest to control light, so that’s where we should put the classrooms,’” McCready recalls. “On the east and the west, the light is very hard to control, so we put things that don’t need as many windows there.”

P.S. 62 daylit corridor. Photo © James Ewing | OTTO.

With these decisions made, the team worked to fine-tune the school’s daylit interiors. McCready describes this process as a science. The goal was to maximize each room’s daylight autonomy: the percentage of the day during which the amount of natural light makes artificial lighting unnecessary. The group tested and refined the design, strategically placing skylights and clerestory windows, sloped ceilings, and light-reflecting surfaces.

The final result is astonishing. The school’s south-facing classrooms achieve 90 percent daylight autonomy. Many of the corridors, which feature generous skylights, reach up to 98 percent. Considering that the building has a very low window-to-wall ratio of 16.5 percent — a metric that contributes to better energy performance — the numbers are even more impressive. For Barrett, it is unlike anything she has seen in her time at the SCA. “I think we have more daylighting than in any school we’ve ever done,” she says. “And because of the design of the interiors, it’s just mind-bogglingly beautiful.”

Building section showing daylight autonomy targets. Image © SOM

Research-Driven Design

In early design studies, placing the number of PV panels required to power the school — more than 2,000 in all — posed a predicament. “They were taking up the entire playground, the entire parking, the entire roof,” says Jon Cicconi, a senior design architect on the SOM team. “I remember looking at fields of PVs on the children’s play area, and thinking, this is ridiculous.”

The architects found a solution by looking within their own office. Working with the Center for Architecture Science and Ecology (CASE), a research laboratory for sustainable design formed in partnership between SOM and Rensselaer Polytechnic Institute, the team worked on optimizing the efficiency of the PV panels by placing them at different angles and in various configurations. These studies led to the development of the school’s distinctive, angled roof structure on which the panels are mounted. By reducing the overall area of PVs needed to power the school, this collaborative product of research and design “suddenly allowed the project to be viable,” Cicconi says.

Redesigning the roof structure to optimize the placement of PV panels increased P.S. 62’s energy output by 221,280 kilowatt hours (kWh), a 35 percent increase. Image © SOM

While the prominent rooftop PV array defines the building’s profile, another important feature is hidden underground. Drilled 420 feet down to bedrock, a system of geothermal wells helps to naturally heat and cool the school, and allows for significant energy savings. This system leverages the constant temperature of the earth to heat the school in the winter, and to transfer heat out of the building in the summer.

The school was designed to require as little energy as possible for heating and cooling. To achieve this, it was critical not only to heavily insulate the building — using materials such as recycled plastic insulation and triple-glazed windows — but also to minimize air and vapor leaks. The team developed a series of high-performance enclosure details to create a virtually airtight barrier. This includes a solution that is also one of P.S. 62’s most visually distinctive features: an exterior rain screen assembled from 30-foot-tall precast concrete panels, tall enough to span the entire building vertically. The panels eliminate the need to puncture the air vapor barrier along the building’s height to anchor the facade. During laboratory tests of this system, Barrett encountered skepticism. “People said, ‘You’re trying to exceed a level of air infiltration that the Army Corps of Engineers has been trying to reach — you’ll never be able to do it.’ But we did even better than we anticipated,” Barrett says.

Diagram of precast concrete rain screen assembly. Photo © James Ewing | OTTO (left) and diagram © SOM (right).

Thinking Like Educators

Through all of these strategies and more, the team had designed a school that would require just half the energy that a typical SCA school consumes. Still, the designers saw an opportunity to go further.

While roughly half of the school’s now-reduced energy use would go toward essential building systems — such as heating and cooling — the other half would depend on the habits of the people using the space. If P.S. 62’s students and staff could reduce their energy use, they would become active participants in achieving the school’s net-zero-energy goal. To encourage this outcome, the architects had to think like educators: How could they teach the building’s users to contribute to its energy performance?

The project team met with senior administrators and faculty at the New York City Department of Education to better understand how teachers and students might use the building. The group found that a significant amount of energy use in a typical school came from classroom appliances — everything from printers to personal refrigerators. During workshops with educators, they learned that teachers often introduced their own appliances in classrooms because the school’s common resources seemed inadequate.

P.S. 62 cafeteria. Photo © James Ewing | OTTO.
Energy reduction data chart. The information depicted is based on design analysis, preliminary in nature, and will need to be verified through the course of the building’s operation. Image © SOM.

Based on these insights, the designers gave special attention to the school’s shared spaces. “We thought, ‘How can we make component pieces of the design more attractive, so that people use them in a collaborative way, a communal way, and a more efficient way?’” Duffy says. “So, let’s talk about sharing printers. Let’s ask the teachers what might make a better lounge — one that they’d actually want to use. Let’s talk to the kitchen staff about not turning all the burners on when they first arrive at school. All of these little things add up to a serious amount of energy.”

By making relatively simple adjustments — equipping the school with spacious, inviting teachers’ workrooms, and providing shared printer stations throughout the building — the designers laid the groundwork for energy saving habits. They also developed a users’ manual for the building to guide teachers and faculty on conserving electricity. The team included the students in this effort as well, working with the design firm Pentagram to develop a system of interactive visual displays. Positioned throughout the building, these dashboards are designed to engage the students as participants in achieving the building’s net-zero goal.

P.S. 62 interactive energy dashboards. Photos © James Ewing | OTTO.

One School’s Big Impact

P.S. 62 opened in September 2015, welcoming its first students into its daylit classrooms and corridors. The project’s impact has already spread beyond the Staten Island community it serves. Having conceived P.S. 62 as a prototype for more sustainable schools, the SCA is updating its own design standards to include some of the features first implemented there. Barrett describes the project as a springboard: “The amount of work was just enormous — ​but having taken the risk, and done the labor and the research, the payoff has been fabulous.”

“There always comes a point where people say, ‘We haven’t done that before…’ Sometimes it’s good to take a risk…and if you’re really focused, you can make it work.” — Bruce Barrett

Each of the SCA’s schools must meet the city’s regulatory requirements, which are constantly updated with ever-more-stringent standards for energy conservation. When new requirements take effect, the SCA has a limited time to implement them — ​often just six months to a year. But with such a large program, “it takes a long time to plan for these things,” Barrett says. So her strategy is to anticipate change, and to find the right strategies before they are needed. “We’re always looking to be out ahead of the curve, so that when new requirements come along, we’re prepared with the solution,” she says.

P.S. 62 main entrance lobby. Photo © James Ewing | OTTO.

As New York City doubles down on its commitment to confront global warming by reducing carbon emissions, Barrett contends that projects like P.S. 62 point the way to the future. “We’re going to have to make deeper cuts on energy use across the board on all of our school buildings, and ultimately on all of the buildings in the city — ​public and private,” she says.

Duffy, too, imagines that P.S. 62 will have an outsized influence. New York’s City’s public school system is the nation’s largest, and its facilities add up to 1.3 million square feet — an opportunity to make an impact at a far greater scale. “This seemingly small project may have great leverage and influence on an enormous amount of building product,” Duffy says. “And those lessons can be applied not only to buildings in New York City, but to other schools around the country.”

Given the environmental challenges that lie ahead, Barrett estimates that P.S. 62 was a risk well worth taking. “There always comes a point where people say, ‘We haven’t done that before — we’re worried that it doesn’t work,’” Barrett says. “Sometimes it’s good to get a little push, and take a risk. And if you’re really focused, you can make it work.”

P.S. 62 gymnasium. Photo © James Ewing | OTTO.