From the Raleigh News and Observer, December 6, 1998
Going underground
By J. Barlow Herget
Correspondent
"I was trying to demonstrate with Eno Commons that we could build houses that use
half the energy that conventional houses use," explains Sherri Zann Rosenthal, a
Durham city attorney and developer of the unique housing project in Durham.
One of those energy saving methods in the 22-home community is the geothermal heat pump that both heats and cools a home. Some who hear geothermal may think of heated underground water like Old Faithful, the spectacular, boiling geyser in Yellowstone Park. But geothermal energy in today's residential home market can be utilized anywhere you find underground water or can bury pipes at least six to eight feet long.
For example, Dick Blosser, president of Geothermal Resources of Raleigh, found plenty of water in a 25-foot well in the small backyard of restaurant owner David Mao's home in Raleigh's Cameron Park neighborhood.
And Bill Evangelist, owner of Evangelist Service Company outside of Apex, had no problem installing underground pipes for Zann Rosenthal's 22 homes on Eno Commons' smaller lots.
Says Bill Bisesi, a building science specialist at Advanced Energy, the non-profit
laboratory and consulting company on North Carolina State's Centennial Campus,
"Geothermal is a very energy efficient system. It lasts longer than conventional
heating and cooling systems." 
He adds flatly, "It's the best heating and cooling system anybody could have."
Today's geothermal systems use the same energy exchange technology used in conventional heat pumps that transfer energy from the air outdoors to heat or cool air that is blown through your home. Only instead of the ambient air, geothermal draws energy from water that enters the home after being at least six to eight feet underground.
The system involves a specially designed heat pump that is located inside the house. Through this unit runs water that comes from either a well outside (an open loop system), or is contained in a closed loop of underground pipes. An open loop system empties the water from the well into either municipal storm drains or into nearby ponds or lakes. This underground water maintains a very steady temperature, around 62 or 63 degrees in the Triangle area.
It is the water's constant, moderate temperature that makes geothermal units more
efficient machines. The air outside can dip well below freezing in winter or hit 100-plus
in the summer, and these extremes make the energy exchangers work harder to produce cool
or hot air. And when the temperature gets around freezing, the heat pump then must use
electric resistance heat which uses - and costs - much more.
Most homeowners are not as interested in the science of geothermal as in the results - especially savings on electric bills. Blosser had one of the nation's largest such businesses in Virginia before moving here in 1993. Asked how much the system costs, he replies, "It's free!"
Explaining, he points to annual electric bills for a typical 2,000 square foot home in the Triangle which total $1,621, according to CP&L.
"A homeowner with a geothermal system will have an electric bill between $400 to $500," Blosser says, drawing from over two decades of experience.
While it varies depending on the home, the savings are substantial.
Advanced Energy's Besesi cites five case studies that his non-profit laboratory conducted two years ago in North Carolina.
"All of the customers were very satisfied with the cost savings," he says. "The case studies show savings along the lines of 40 percent annually."
The systems themselves, however, are more expensive than conventional HVAC units. The heat pumps themselves cost more, and the underground piping and/or digging wells make geothermal systems cost 1 1/2 to two times more than conventional systems. It is this extra, initial cost and the reluctance of HVAC contractors who are unfamiliar with such technology that has slowed the growth of geothermal systems.
Bill Evangelist, who installs and sells both conventional and geothermal systems, has promoted geothermal for years. He installed a system in his home 15 years ago. Since then, he has installed about 150 such systems in the Triangle, most of them closed loop units in new homes for customers such as Zann Rosenthal.
He says, "I have no unhappy customers. The systems do everything we say they'll do."
One of the things that the systems do, besides reducing electric bills, is to run quietly. The maintenance costs are typically lower, too.
"You eliminate outdoor equipment," he explains, which cuts down on wear and tear from weather and yard debris.
Zann Rosenthal supplies the proof in the pudding.
"We have two models at Eno Commons, a 1,500 square foot home and an almost 2,000 square foot model," she says, emphasizing that the houses also use passive solar designs, metal, radiant barrier roofs and very effective wall and duct insulation.
The homes cost between $142,000 and $174,000.
She figures the attention to energy saving technology including the geothermal systems added about $4,000 on average to each house. But for homeowners who moved in this summer, the electric bills during the blistering heat of July and August averaged about $55 a month!
"The units are top of the line. The fans ramp up slowly, so they're very quiet. They have high quality thermostats and the variation in temperature [between the time the machines are on and off] is only about two degrees," she reports.
While it has taken her from 1995 until now to bring the project to fruition, Zann Rosenthal is encouraged by her experience.
"People are really more farsighted and want to do the right thing for the environment. The savings starts the day you move in. I want to try and get our local builders thinking about this."
As for her plans, she adds, "I'm looking at projects now."
For more information on geothermal systems, contact Bill Bisesi at Advanced Energy, 909 Capability Dr., Suite 2100, Raleigh, N.C. 27606 or call (919) 857 9024.
Barlow Herget is a former member of the Raleigh City Council and helped write the state's 1977 Energy Conservation Acts.