FAQs about Geothermal

You’ve probably got a lot of questions about geothermal. We’ve responded to some of the more frequent questions we get to help you make your decision. Please contact us if you want to learn more.

Will my electric bill go up? If it does, by how much?

Yes, your electric bill will go up. BUT — and here’s the big point, the increase will be about 30% to 60% of your existing FUEL costs. For example, if you typically spent $3,000 a year on propane for heating, your electric bill might go up $1,200. But that would make for a savings on your FUEL costs of about $1,800.

Why the variation of 30% to 60%?

Each home is unique. A drafty, uninsulated, old farmhouse would be different from a new ranch, insulated tight and ventilated correctly. That’s why we do Manual J calculations — to take into account the very individual characteristics of your home. We might even suggest that you consider a home energy audit to determine where energy might be being wasted. The savings also vary with the type of fuel that you will be replacing with geothermal.

How do you size an installation?

ACG provides a thorough heat/gain loss calculation to determine the tonnage needed to adequately heat and cool a building. Most HVAC contractors do not offer this service. The size of all equipment and the loop field is based on the tonnage needed. For example, a four-ton system requires a four-ton heat pump and four 400-foot-long trenches.

Is geothermal only for rural residences?

Not at all. A large city lot could accommodate a horizonal loop, depending on the size of the system. Or, a vertical loop system could be installed. For a four-ton system, they would typically require a 20- by 20-foot area for vertical wells. City ordinances vary but generally are not an issue for geothermal closed loop fields.

How do open and closed loop systems differ?

An open loop, also called a “pump and dump,” needs an adequate water source. It uses groundwater from a well as a direct energy source. That water is then “dumped” into a nearby stream, lake or floodplain. Mineral deposits and water quality may cause maintenance issues. A closed loop circulates a pressurized mix of water and methanol through the loop field. A four-ton system needs about 120 gallons of the mixture.

How can a geothermal system provide hot water?

When a system is equipped with a desuperheater, the desuperheater transfers any excess heat from the geothermal heat pump’s compressor to the home’s water tank or, in some cases, a spare tank from which the water tank draws. In the summer, when the system is removing heat, a portion of that waste heat is diverted to heat the water in the tank.

What’s the expected life of a geothermal system?

The WaterFurnance equipment that we install comes with a 10-year parts and labor warranty. We fully expect the units to last 20+ years. The ground loop should last 50+ years. A separate 50-year warranty from WaterFurnace can be added to the purchase that would cover the cost of replacing the loop field.

Is loop field fluid at a constant 55 degrees F?

No. But the equipment operates efficiently with entering fluid temperatures as low as 28 degrees. In October and November, when we typically start the heating season in Wisconsin, the entering fluid temperature can be 55 to 60 degrees F. By late March, after heat from the heat source has been withdrawn for months, the same entering fluid could range in temperature from 28 to 36 degrees.

ACG, LLC | P.O. Box 255 | Kiel, WI 53042
920-894-3999 | FAX 920-894-1389


Serving customers in the communities of Reedsville, Lomira, Plymouth, Sheboygan Falls, Hilbert, Brillion, Kewaskum, Theresa, Kohler, Kiel, Chilton, New Holstein, Appleton, Sheboygan, Howards Grove, Elkhart Lake, Fond du Lac, Manitowoc, Calumet, Sherwood, Cleveland, Valders, St. Nazianz, Fredonia, Cedar Grove, Belgium, West Bend, Cascade, Waldo, Ripon, Rosendale, Eden, Newton, School Hill, St. Cloud, Wrightstown, Kaukauna, and Kimberly and throughout the counties of Brown, Calumet, Dodge, Fond du Lac, Green Lake, Jackson, Juneau, Kewaunee, Manitowoc, Milwaukee, Outagamie, Ozaukee, Shawano, Sheboygan, Washington, Waushara and Winnebago.

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