Building a Sustainable School on a Shoestring

To avoid catastrophic climate change, experts say developed nations must reduce their greenhouse gas emissions by at least 80 percent by mid-century. Getting there will take major improvements in energy efficiency, particularly in energy-intensive buildings.

While 80 percent might sound like a tall order, good design principles and conservation techniques can already get a building close enough to carbon neutral for technology to finish the job, says architect Lawrence Maxwell, president of Spacecoast Architects of Indialantic, Fla.

Step one in sustainability, he says, is to reduce energy load.

The Odyssey Charter School, Maxwell’s prototype for a sustainable school design, comes close to meeting that 80 percent cut. It needs less than 30 percent of the energy required by a typical school.

The school demonstrates how to program high-energy performance into a building’s DNA using principles of building orientation, natural lighting, natural ventilation, advanced thermal envelope design, active and passive thermal storage, and demand management.

“Energy performance was achieved with natural, simplistic means using everything we know about how things work [energy-wise],” Maxwell says.

This aesthetically attractive, 47,000-square-foot school also cost half as much to build as a conventional school, $70 per square foot compared to $150 per square foot, without sacrificing comfort or facilities.

The first Odyssey school, built in 2005 in Palm Bay, Fla., easily qualified for the EPA’s new Designed to Earn the Energy Star rating, earning 95 out of 100 points. Commercial buildings must earn at least 70 points to qualify.

The program was designed to provide architects with the tools to design buildings that meet ENERGY STAR performance standards, says Karen Butler, the EPA’s manager of Commercial Building Design for Energy Star. Using the online Target Finder tool, a free service of the EPA, designers can enter data and evaluate the level of energy performance the design will achieve when it is built.

The tool allows architects to compare design alternatives to enhance energy efficiency. It also lets them select target designs to meet American Institute of Architects' Sustainable Practice and its 2030 Commitment goals, which aim for 100 percent carbon-neutral design within 20 years. Right now, buildings are responsible for about 40 percent of U.S. energy consumption. The tool provides a pathway for mapping carbon reduction along with energy performance, Butler says.

Designing for Natural Light

At the Odyssey school, energy efficiency began outside with proper site orientation; a thermally efficient building envelope with exterior insulation and finishing system on tilt-up concrete; use of light-colored, reflective metal roofing; and maximum levels of roof insulation.

A north-facing clerestory of 12-inch windows along the classroom roofline and row of four-foot-high windows at eye level capture indirect light without the heat, minimizing the air-conditioning load.

Sloped ceilings in the 26 classrooms increase daylight from the north and south and help balance the light distribution. Beginning at nine feet, the ceiling slopes up to 11 feet, then at the room’s midpoint shoots straight up 14 feet to the clerestory of windows, creating a skylight effect.

A light-colored roof also shades the windows while reflecting indirect, natural light into classrooms, minimizing heat gain.