Geothermal heating and cooling have been associated with geologically active locations of the world. So it’s surprising to discover that this eco-friendly approach to indoor environmental conditioning is also taking root in geologically stable New York City. More than 100 permits for geothermal wells have been filed with the city’s Department of Environmental Conservation in the past eight years, and 35 such wells are in operation in Manhattan. Using geothermal heating and cooling systems lowers utility bills by as much as 70 percent versus conventional HVAC systems, according to trade group Geothermal Heat Pump Consortium (GHPC).

In Manhattan’s bedrock, geothermal activity ­begins to become evident at about 1,100 to 1,400 feet, where the temperature holds steady at about 52 ­degrees F.

As a rule of thumb, the average geothermal system costs about twice as much to install as a conventional heating and air conditioning system, according to John Kelly, executive director of the GHPC. Not surprisingly, they’re considerably more expensive to install in dense urban areas such as New York, where one installation in a condominium reportedly cost $150,000 more than a conventional HVAC system would have. While the hardware and technology costs are roughly on par with those of conventional systems, the cost of drilling is usually what doubles the price. However, geothermal systems typically have lower life-cycle costs than any other heating/cooling system, conventional or otherwise, thanks to the simplicity of their design. Geothermal heating and cooling costs for a typical 2,000-square-foot home can run as low as $1 a day.

Kelly says that more than one million geothermal HVAC systems have been shipped in the ­U.S. since 1994, with half of them intended for residential construction. The federal government’s Energy Information Administration reported 63,682 geothermal heat pumps shipped in 2006 (the most recent year for which data are available), a 33 percent increase over the 2005 total of 47,830. “When the housing market returns, you’ll see geothermal posting bigger numbers than ever, because the memories of heating oil and electricity costs of the past few years will remain quite vivid in the minds of consumers,” he says.

Learn more about markets featured in this article: New York, NY, Manhattan, KS.