Green schools are emerging around the country, and they are nothing short of spectacular. Whether built from the ground up or retrofitted, they are awash in daylight and the glow of natural wood, equipped with individualized air, light, and temperature control, and surrounded by rich landscapes designed to shade and regenerate our air and water.
Green schools cost less than 2 percent more than conventional schools to build but provide 20 times the financial benefits, according to author Greg Kats. Even in existing schools that are making smaller changes to lighten their impact on the planet, the benefits are obvious: savings in energy, water, materials, land, and transportation. In a 2006 study of 30 American schools, Kats identified an average 33 percent reduction in energy use and a 32 percent reduction in water use in green schools (as defined by the U.S. Green Building Council) when compared with conventional schools.
Less well known are the seemingly invisible assets of environmentally healthy buildings. A school designed to have a smaller carbon footprint can also have a big impact on the learning and health of its students, improving test scores, reducing absenteeism, advancing new levels of learning, and reducing asthma and allergies. Good ventilation, daylight, cleanliness, reduced noise -- all attributes of green design -- are not merely aesthetic improvements; they can actually promote better educational outcomes.
Proving the Power of Green
Recently, as a member of a National Academy of Sciences committee, I reviewed a large pool of research related to standards developed by the Collaborative for High Performance Schools and the USGBC's Leadership in Energy and Environmental Design (LEED) certification system.
Quantifying the health and learning benefits of green schools is not easy, because there are so few studies available. But our report, "Review and Assessment of the Health and Productivity Benefits of Green Schools," concluded that a number of green-school attributes are vital to health and learning.
To begin with, green schools take the challenge of keeping water out -- a necessity for health -- to a sophisticated level. Green, dry schools are designed to capture rain for landscape irrigation and use recycled water in the building. Second, green schools are designed to be well insulated, without "thermal bridges," or cold surfaces, that might result in condensation and water damage.
Managing excessive moisture in the form of leaks, visible dampness, or visible mold has been associated with reduced asthma and respiratory disease in schoolchildren. In a 2002 study of 32 schools in Finland, researchers identified an average 15 percent reduction in the prevalence of the common cold during springtime in school buildings that had no moisture or mold problems as compared with moisture or mold-damaged schools.
Green schools are designed to have excellent indoor air quality. Reducing indoor pollutant sources, providing adequate quantities of outside air, and ensuring maintenance of the filters and ventilation system have been linked to reducing absenteeism and improving teacher productivity and student learning. In a 2006 study of 54 elementary schools, researchers identified a 14.4 percent improvement in standardized math test scores in classrooms with a ventilation rate that was double the norm.
Local thermal comfort also has a measured impact on student achievement. Better windows as well as walls and floors that do not get too cold or too hot are elements of green-school design, as are up-to-date controls with careful commissioning of mechanical systems.
The next generation of green schools must go even further. They should provide each teacher with local temperature controls independent of fresh-air delivery, along with the ability to open high and low windows to provide a quick refresh of room air without drafts. Future buildings also must manage solar overheating with awnings and shades that do not eliminate light or view.
Most green school buildings are designed or retrofitted to be quiet, managing traffic noise, room reverberation, and noise transmission between rooms. Managing noise in classrooms has been shown to improve student learning and the development of language skills, as well as protecting teachers' vocal cords.
In a 2002 study of 10 preschools, researchers in Stockholm found an 11 percent reduction in vocal strain among teachers in quiet classrooms (with background noise levels of about 55 decibels) as compared with those in noisy classrooms (at a surprisingly common 75 decibels).
Green schools -- both new and renovated -- also are designed to be easy to clean, a necessity for good indoor air quality. Keeping desk and contact surfaces disinfected to help prevent the transmission of infectious diseases and implementing pest-control measures to help control indoor pollutants -- all green-school attributes -- have been associated with reduced levels of respiratory disease.
Finally, when building systems are commissioned to meet the intent of green design, and routine preventive maintenance continues throughout a building's life cycle, the likelihood that the building will remain dry, comfortable, quiet, and clean grows, as do the satisfaction and performance of teachers, students, and administrators.
A Bright Green Future
Some of my favorite attributes of green schools -- daylight, links to outdoor classrooms, and school buildings that serve as labs -- deserve further study to demonstrate their importance to health and learning across the nation.
Green schools almost always are designed around daylight in every space and around views of nature. As long as windows are controlled to eliminate glare and summer overheating, they provide benefits for students and teachers alike: higher light levels without energy costs, excellent illumination of educational materials, and views of nature and the passage of time. Visual access to the outdoors, from morning to night and season to season, is important to our circadian rhythms and our sleep cycles.
One of the most famous school-building studies, completed by the Heschong Mahone Group, identifies test scores 7-26 percent higher for schoolchildren in classrooms with plentiful natural light than for those in classrooms with little or no daylight. Windows also can support natural ventilation, especially with high and desk-height windows that provide free cooling through most of the academic year and let outside air flow into stuffy classrooms as needed.
Ideally, green classrooms are linked to outdoor learning and recreation spaces. The importance of physical activity and of outdoor learning through three-dimensional playgrounds, edible gardens, and nature walks has been highlighted by organizations like the Children & Nature Network and in books such as Richard Louv's Last Child in the Woods.
In a 2008 field study of 17 children diagnosed with attention deficit hyperactivity disorder in Urbana-Champaign, Illinois, researchers identified a 17 percent improvement in concentration performance at memory tasks after a 20-minute guided walk in a natural park as compared with a walk in a downtown setting or a residential setting.
Although not a standard characteristic yet, green schools should be within walking distance of students and teachers. Green schools in neighborhoods designed for walking, or at least in transit-oriented communities where some walking can be assumed, provide recreational and meeting spaces that support the community, improve neighborhood safety and vitality, and ensure the immeasurable benefits of physical exercise.
A San Diego study identified 60 percent obesity rates in low-density, "nonwalkable" neighborhoods as compared with 35 percent in "walkable" neighborhoods.
Finally, green schools should be rich with environmental materials and learning -- a living laboratory for children. Our role in climate change is the topic of the century, with environmental curriculum emerging at every level of schooling.
At the same time, educational researchers emphasize the value of hands-on and tactile learning and of experimentation to engage and capture the interests of students. The opportunities to understand the flow of heat, light, air, sound, and energy in buildings and to teach the science, the math, the history, and the art of innovation for our shared future is most powerfully delivered when the school is a living laboratory.
Our commitment to the environmental quality of our school buildings, in both new and renovated schools, must go hand in hand with our commitment to environmental education and to education that is effective in a highly competitive global economy.
The environmental benefits of green schools are becoming clear; the health and performance benefits now need the spotlight. Going a step further and designing our schools to be environmental learning labs will help create a new generation of green consumers, inventors, installers, and educators. It is a brilliant cycle of win-win both for the Earth and for our children.