Prakash Patel

In 2009, the City of Manassas Park, Va., expanded Manassas Park Elementary, which served kindergarten through third grade, to include fourth and fifth graders, as well as pre-K learners. The two-building project also sought to give students a greater connection with nature, via the wooded preserve adjacent to the campus as well as an outdoor classroom that doubles as a stormwater bioretention facility. Ensconced in glass, the school features no space, be it hallway, office, or classroom, without a view to the outside. And even in an era of security, Manassas Park Elementary makes outdoor learning part of its daily curriculum.

Students are seeing the light—and it's green. Classrooms are equipped with a green light that shows when temperature and humidity levels are suitable for opening the windows. “When that light goes green, oftentimes it’s not just the teachers driving that effort [to open the windows]. It’s the kids,” says Stacey Mammon, principal at Manassas Park Elementary and Pre-K. “They start asking to open the windows. It’s really powerful having that ownership of their school and what’s happening in it.”

The project’s design team, led by Charlottesville, Va.–based VMDO, made sure to measure energy, water, and other resources from the beginning, enabling even this relatively new structure to provide teaching tools after just three years. Next door, the existing Cougar Elementary school (which opened in 2001) also provided a point of comparison, housing the same number of students and using the same maintenance staff. All told, the lesson is that the right combination of design and material selections, as well as occupant buy-in, can save a lot of energy.

Designed to meet the 2030 Challenge and to use half the energy of a code-compliant school, Manassas Park Elementary features an airtight, spray foam–insulated envelope and efficient geothermal heating and cooling system (consisting of 221 closed-loop wells), the latter of which pairs with a separate heat pump for each classroom to condition air only as necessary.

In its first year, the school used 37.28 kBtu per gross square foot, compared to a national average of 70 kBtu for K–12 schools. The new buildings also used 40.4 percent less energy than Cougar Elementary, saving about $50,000. The second year, Manassas Park Elementary used 46.3 percent less energy than Cougar, saving almost $65,000 dollars. “That had to do with fine-tuning the new building,” explains architect Wyck Knox of VMDO. The pumps running the geothermal system, for example, were supposed to operate at variable speed based on need, but had been running at full speed all the time. “What I think is noteworthy is that it wasn’t discovered by commissioning or an outside party,” Knox adds, “but by the design team and the owner sharing data and saying, ‘Something’s not right here.’ ”

In the past 12 months, the school has operated a full 40 percent better than the K–12 baseline. “Once they saw how much money they were saving, they decided to hold summer school for the entire system in Manassas Park Elementary, and put the district’s three other schools into unoccupied mode. System-wide, the school system is saving more money,” Knox says.

If the energy-efficiency efforts were a home run, results for water usage are more of a solid single. It’s not that water isn’t being saved. Manassas Park Elementary is using 1.74 million gallons less than Cougar Elementary, for a savings of $24,290. But because water in the region is relatively cheap compared to energy, the savings are less significant. “The payback on rainwater-harvesting systems is very long,” Knox says. “If you put it into real life-cycle cost analysis, it’s hard to justify.”

Even so, the water efficiency—using stormwater to irrigate and flush toilets—is a worthy educational tool. “At first, kids thought the rainwater was going right into the drinking fountains. We did have to correct misconceptions,” Mammon says. “We like to say we learn in the building and we learn from the building. That’s always happening.”

Brian Libby writes about architecture from Portland, Ore.