LACONIA, N.H. — The guests at Maurice and Helene Gouin's bed and breakfast come to swim and fish in Lake Winnisquam, cruise in Gouin's solar-powered launch, or simply gaze across the water as they eat blueberry pancakes with homemade maple syrup.
But Lake Winnisquam is more than just a beautiful view and a refreshing dip for the guests at Rest Assured. It also provides the energy that heats and cools the three-story, 4,800-square-foot house on the lake's edge.
From the second-story porch off the kitchen, Gouin points out the white-painted logs that hold down a 1,500-foot loop of plastic pipe on the lake bottom. Water mixed with antifreeze runs through the loop and back into a geothermal heat pump in Gouin's basement.
The heat pump exploits the temperature difference between the lake water and a refrigerant gas to heat Rest Assured to 70 degrees in winter, cool it to 72 degrees in summer and supply two-thirds of its hot water. The cost is about $700 a year in electricity, a bargain by any measure.
"It's nothing but a refrigerator, basically," Gouin explains. "When you put food in the refrigerator, you take heat out of the food and dump it in a coil in the back of the refrigerator. This is just a bigger unit."
Geothermal systems--which consist of a heat pump connected to piping buried in the ground, laid on a pond bottom or run down a well--are taking off, thanks to a push by the government and electric utilities.
A 1993 study by the U.S. Environmental Protection Agency found that geothermal systems are the most energy-efficient, least-polluting space-conditioning technology available today in most of the country.
Heat pumps cost up to two-thirds less to operate than electric baseboard heat or conventional fossil fuel furnaces and hot water heaters. The savings are smaller but significant on air-conditioning.
An electric-powered heat pump uses only one-third as much power as electric baseboard heating and conventional air-conditioning, meaning it is responsible for only one-third the carbon dioxide, sulfur dioxide and nitrogen oxide emissions. The coolant in the pipes meets new EPA standards banning chlorofluorocarbons that can destroy the ozone layer.
Heat pumps also generally are safer, steadier, quieter and less obtrusive than conventional systems, their advocates say.
So why aren't they more popular?
Mostly it's a matter of getting the word out, said Paul Liepe, executive director of the Geothermal Heat Pump Consortium, a public-private group formed in 1994.
"It's an extremely well-kept secret that we don't want to keep," Liepe said.
The consortium is hoping to increase the annual number of geothermal installations from 40,000 to 400,000 by 2000, by teaching builders how to install them and educating mortgage lenders about their advantages.
Although the basic technology has been around since the 1940s, it is only in the last 10 or 15 years that it has become extremely reliable and adaptable to almost any climate or site, Liepe said.
Because the ground maintains a constant, year-round temperature only 7 feet below the surface, it acts as a heat source in winter and a heat sink in summer. The free energy is extracted and transferred by the heat pump, which can be powered by electricity or natural gas.
The biggest barrier for many homeowners is a lack of understanding about geothermal systems and a shortage of builders who know how to install them, said Carl Orio, president of Water & Energy Systems Corp. in Atkinson, a distributor and designer of geothermal systems.
Also, geothermal systems can cost about $4,000 to $5,000 more to install than conventional systems because the homeowner must drill wells or dig a trench to bury the pipe loop, Orio said.
The cost goes down if the homeowner can use a single well for drinking water and a geothermal system, Orio said.
Some utilities subsidize geothermal installations. Even without subsidies, geothermal systems typically pay for themselves in about three years, Orio said. Over 10 years--even with a higher monthly mortgage payment for the installation--someone in an energy-efficient, 2,000-square-foot home in southern New Hampshire would save nearly $13,000 compared to a homeowner with a propane furnace and hot water heater, he said.
The savings are lower and may not offset the higher installation cost in areas where the climate is mild or energy costs are low, said Kevin Rafferty, associate director of the Geo-Heat Center at the Oregon Institute of Technology in Klamath Falls.
For commercial buildings, however, the installation costs for geothermal heating systems often are the same or lower than for conventional heating and cooling, Liepe said.
When the Manheim Township School District in Lancaster County, Pa., renovated and expanded the Neff Elementary School, the geothermal system cost $13.69 per square foot to install--less than conventional systems at the Reidenbough Elementary School built four years earlier.