When the architects of the Yorktown High School renovations presented their designs to the public last month, they touted their use of glass walls that would bring natural light into the building and make it more energy efficient and environmentally friendly.
But an official with Arlington Public Schools (APS) told the Connection that this couldn’t be further from the truth.
"There’s never an example where glass makes a building more efficient," Kevin Chisholm, the energy manager for the APS Design and Construction Department, said. "It always reduces the [energy] efficiency of the building."
He said that designing an efficient heating and cooling system for a building that uses a large amount of glass is nearly impossible because of the great degree of temperature variability that comes with transparent walls.
To illustrate this point, he brought up Langston Alternative High School, which was rebuilt with glass walls four years ago. Chisholm said that "[Langston’s] library is not utilized the way it should be because it’s uncomfortable to be in six months out of the year." Langston administrator Cleveland James confirmed this, saying that heating the library is difficult and that "it can be uncomfortable at times."
Chisholm also said that glass walls are "very difficult and resource-intensive to clean." In this way the use of glass increases a building’s long-term costs.
Chisholm said that he is not diametrically opposed to the use of glass in buildings but believes it should be done in moderation. "We try to encourage a balance," he said, "but there’s no reason to go all glass."
EHRENKRANTZ ECKSTUT AND KUHN ARCHITECTS is the design firm that contracted by APS to redesign Yorktown High. They presented their schematic design to the public in late January but refused to respond to Chisholm’s claims and, instead, deferred all comments to Sarah Woodhead, director of the APS Design and Construction Department.
She agreed with her colleague that glass is not the most efficient building material that could have been used and acknowledged that energy efficiency is an important factor in designing a building.
But Woodhead said that it should not be the most important factor. "Any building is going to be balancing [a lot of] competing needs," she said. "But we would never want to forego [using] glass in a school."
She recalled the school designs of the 1970s when efficiency was considered paramount by architects and the use of glass in buildings was frowned upon. "[Back then] they built buildings with no windows," she said. "Those old schools were like prisons and people blame architects for this. We don’t want to repeat those same mistakes."
The dramatic change in thinking on this issue can be attributed to a landmark 1999 study by the Herschong Mahone Group, an architectural analysis firm based out of California, titled "Daylighting in Schools." Herschong Mahone analyzed the test scores of more than 21,000 students and determined that academic performance is significantly higher in schools with the most natural daylight.
"We want daylight into every building [we build] because it is healthier and increases school performance," Woodhead said.
Michael Bednar, a professor of architecture at the University of Virginia, agreed with this. "Kids are able to learn better with natural light," he said.
Chisholm said that "most reasonable people in our business agree with this." But he warned that the use of glass is so inefficient that architects should be very careful not to give into current building design trends and overuse it.
WOODHEAD SAID SHE IS AWARE of these concerns about the efficiency of the new Yorktown High. But she said that the amount of glass that is being used in the renovation has been overstated.
"When you look at the drawings you can’t really see what is glazed and what is not," she said. "There are some areas that have a lot of glass [but] they are judiciously placed to get the most out of it."
And while glass is less energy efficient than other building materials, Woodhead said that the type of glass that will be used in Yorktown is highly insulated and that will help mitigate any kind of heat loss.
Chisholm was skeptical about this, however. "They haven’t invented an efficient type of glass yet," he said.
Bednar said that, ultimately, the use of glass in a building is a trade off between energy efficiency and other factors. He said that an architect’s decision to use glass in a building is never a simple one. "Usually, using natural light is a good idea," he said. "But only to a [certain] point. It is a complex equation."