Green schools cost less than 2% more than conventional elementary, middle and high schools but can provide financial benefits that are 20 times as large, according to a recent study of 30 high-performance schools. Beyond the first cost of a green school, sustainable designs enhance student learning and reduce health and operational costs, says the study.

On average, nationally, schools cost $150 per sq ft. A green school, on average, costs $3 per sq ft more, says the study. But the extra first cost is made up quickly. Energy use is, on average, lowered by 33% over a conventional school. Reduced gas and electricity use translates to lower pollutant emissions. Study schools also used 32% less water. This saves not only at the school level but is “beneficial” to society because of a reduction in infrastructure costs to deliver water and to transport and treat wastewater, says the report.

The case for green schools is laid out in “Greening America’s Schools, Costs and Benefits,” authored by Greg Kats, managing principal of Capital E, a Washington, D.C.-based “green” consultant, with Jon Braman, Capital E’s contributing researcher. The study was sponsored by the American Federation of Teachers, the American Institute of Architects, the American Lung Association, the Feder-ation of American Scientists, the George Gund Foundation, the Kendall Foundation and the U.S. Green Building Council, which produces the LEED building rating system.

Using LEED’s definition of a green building, the report culled data from 30 green schools in 10 states, built from 2001-2006. Much cost data is from the school architect. Some energy data is from building performance and some is from design modeling.

Next month, USGBC plans to release LEED for schools, says the report. Among subjects addressed are acoustics, master planning, mold prevention and joint use of facilities.