Despite Steep Upfront Cost, Geothermal Systems Sharply Cut Energy Bills
By Catherine Idzerda, The Janesville Gazette, Wis.
Jul. 9–Last winter, Denny and Susan Wright saved a couple hundred dollars a month on their heating bills without resorting to the phrase “Go put on a sweater.”
No kidding–a couple hundred dollars, and without having to wear hats and mittens in the house.
And this summer when they use their air conditioning, they’ll barely see a blip on their electrical bill.
The Wrights are one of the few Rock County families who have discovered the benefits of geothermal heating and cooling, a system that uses natural resources in an unusual way.
“Natural resources” usually refers to a fuel taken from the ground, combusted and never used again.
But geothermal systems rely on a different natural resource: The earth’s heat.
“Ground loop heat pumps have been around for about 50 years, said Clay Kohlhagen, co-owner of Don-Martin Heating and Cooling, one of the few local companies that installs such systems.
Here’s the most basic way to explain it:
Between 6 and 8 feet below the ground’s surface, the temperature is about 50 degrees.
Pipes are run into the ground, either vertically or horizontally, depending on the amount of space that’s available.
During the winter, the fluid-filled pipes absorb the heat of the earth. The system transfers it through a compressor and brings it back into the house.
During the summer, the system takes the heat from the house, transfers it to the fluid and back into earth.
Homeowners control the system through a traditional wall-mounted thermostat.
The system relies on a basic principal of high school physics: Energy moves from areas of high concentration to low concentration, seeking balance. Think of what happens when you put ice cubes into a glass of water. The cubes absorb the warmth around them and begin to melt, and eventually you just have water that’s all the same temperature.
Electricity is used to run the compressor and blower, but it’s a minute amount compared to the cost of running a traditional furnace or cooling system.
The savings are incredible.
Schools and municipalities are turning to geothermal as a way to cope with rising energy bills. The Evansville School District uses such a system, and the Clinton School District is considering it for new construction.
So why don’t all homeowners install such systems?
It’s the upfront costs that are hard to get past.
The cost of the interior unit is about the same as a high-efficiency furnace and air conditioning unit.
However, installing the ground unit requires an additional contractor to dig the trench for the horizontal systems, or a well digger to drill and install the pipe for the vertical systems.
“I usually tell people to expect an additional $12,000 for installation of the loops,” Kohlhagen said.
Denny Wright said his expenses were less.
He lives in an old farmhouse in Newark Township, and the total cost of his system with the indoor unit and outdoor work was $15,000.
Wright, a farmer, thinks the systems would be much less expensive for new construction.
“The equipment is already out there at the site,” Wright said. “When they’re putting in your basement, they can dig the trench and put in the loop.”
As little as a decade ago, such systems wouldn’t have been worth the money because energy was cheap.
“Natural gas has gone up 250 to 300 percent,” Kohlhagen said. “Nobody imagined that would happen.”
How much will you save in heating and cooling bills?
“Every house is different; you don’t know if they have kids who are coming and going or a dog that’s in and out,” he said. “Usually, I say between 50 percent and 70 percent.”
The Wrights saw a significant savings in their first year.
For the winters of 2005-06 and 2006-07 they “pre-bought” 800 to 1,000 gallons of propane at $1.60 a gallon. By buying propane in advance, they got the best deal.
Using the 800-gallon figure, that’s $1,280 in propane.
During the three coldest months of those years, December, January and February, their heating and electric bills were $175 to $200 a month.
Using the $175 figure, that’s $525 for a winter.
Total with propane and electricity, $1,805.
Keep in mind, too, that those two winters were relatively mild.
Last fall, they pre-bought 100 gallons of propane to run the stove and hot water heater for three months. At $1.60 a gallon, that’s $160 for the winter.
During the coldest months of the winter of December, January and February, their total utility bills were about $230 a month.
Total bill with propane and electricity: $850. That’s a decrease of almost $1,000.
And Wright estimates they still have at least half a tank of propane left.
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Copyright (c) 2008, The Janesville Gazette, Wis.
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