Home Heating from Deep in the Earth a Money Saver



GOULDSBORO — Kathe Brown of Wilmington, N.C., is spending more time in Maine looking after her elderly mother, so she decided to make her own home here more energy-efficient.

She recently installed a geothermal system in the 1,500-square-foot house on Route 186 that was built in 1903 by her great-grandfather, Henry Cobb Bunker.

“I’m a tree hugger, so I like the idea of saving energy,” said Brown. “I’m happy to help the effort for renewable energy.”

Geothermal systems use heat from the earth to heat and cool homes and much larger buildings, such as the Ellsworth Elementary-Middle School.

The system installed by Pine State Drilling of Athens at Brown’s home over the last several weeks includes a 500-foot-deep bore hole, ground source heat pump, flow center and a new heat pump electric hot water heater.

A water and antifreeze solution is circulated from the ground to the home in a closed loop piping system. A heat pump removes heat from the circulating water and delivers the energy to either an air or hot water baseboard system.

In warmer months, the home is cooled when the fluid takes heat from indoors and transfers it back into the earth.

GEO Thermal Exchange Systems can range in depth from 10 to 600 feet deep.

The paybacks on the $33,824 geothermal system in Brown’s home, plus $8,300 in energy conservation measures, are expected to take nine years.

Geothermal Savings at EEMS

Last year is the first full year of data available for the geothermal system installed at Ellsworth Elementary-Middle School, but the initial results look promising.

David Bridgham, business manager for Regional School Unit 24 (RSU 24), said the heating and electric costs at the 200,000-square-foot EEMS are almost comparable to Ellsworth High School, which is about 125,000 square feet.

Last year RSU 24 spent $248,838 on electricity and heating oil at EEMS and $244,275 at the high school, he said.

“The water in the wells with heat pumps heats up to just over 60 degrees and the oil heat kicks in above that,” Bridgham said. “You’re not heating from sub zero up.”

Although the expense for electricity was proportionate for the size of the schools, the heating oil costs at EEMS were substantially lower—26 cents per square foot compared to 95 cents per square foot at the high school.

Bridgham said EEMS has additional energy saving features such as more efficient lighting fixtures and lighting that turns on and off with motion sensors.

Geo What?

The adjective geothermal originates from the Greek roots geo, meaning earth, and thermos, meaning heat.

Geothermal energy is thermal energy generated and stored in the Earth. Thermal energy is the energy that determines the temperature of matter.

About 20 percent of Earth’s geothermal energy originates from the original formation of the planet and 80 percent from radioactive decay of minerals.

The geothermal gradient, which is the difference in temperature between the core of the planet and its surface, drives a continuous conduction of thermal energy in the form of heat from the core to the surface.

For more of the latest news, pick up a copy of The Ellsworth American.

Jacqueline Weaver

Jacqueline Weaver

Reporter at The Ellsworth American
Jacqueline's beat covers the eastern Hancock County towns of Lamoine through Gouldsboro as well as Steuben in Washington County. She was a reporter for the New York Times, United Press International and Reuters before moving to Maine. She also publicized medical research at Yale School of Medicine and scientific findings at Yale University for nine years.[email protected]
Jacqueline Weaver

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