Thomas R. Grover Middle School

Under the grassy athletic field are 300 vertical pipes, extending 250 feet below the earth's surface. Coursing through them is a mixture of water and antifreeze that slowly warms underground, where the temperature stays close to 55 degrees no matter what the mercury says above ground. That warmed mixture returns to the school and has the heat extracted from it. The heat is then blown into the building by a heat pump. This same GEOthermal process cools the building in the summer.
Experts estimate that around 100 commercial buildings and some 2,500 homes in the Garden State have them.

More recently, schools in New Jersey and nationwide have been going geothermal in increasing numbers. "It has absolutely been an explosion," said Mike Fischette, the co-owner of the Cherry Hill-based Concord Engineering Group, which designs the systems.

At the Thomas Grover school, heating and air conditioning costs are about 20% less than they would be otherwise. "I have found no negatives," said Robert Austin, the executive VP of educational services at Concord Engineering Group. "This is absolutely amazing technology."

The biggest plus, experts say, is that geothermal systems don't burn fuel , and use far less electricity than traditional systems. Also, unattractive rooftop fans and cooling towers are unnecessary, allowing schools to have sloped roofs if they want.