2018 IGA Conference Tentative for 2/6 & 2/7/2018

About Geothermal

Commonly Asked Questions

A geothermal heating and cooling system works on the simple fact that the earth below the frost line (In Iowa around 4 feet down) is a constant temperature of around 50 degrees year round. Using the principles of refrigeration, heat can be taken from the ground and transferred through a heat pump to the air in your home during the winter. In the summer, the process is reversed and the heat in your home is transferred to the ground to cool your home.


Main elements of a geothermal system include:

  • Buried loops of plastic piping (either horizontal or vertical) call the ground loop

  • A biodegradable liquid antifreeze

  • A pump to circulate the antifreeze through the ground loop

  • A heat pump


The ground loops are buried in the ground and are connected to the circulating pump inside your home. The pump circulates the water-biodegradable antifreeze through the buried ground loops and the liquid mixture absorbs heat from the ground as it circulates through the loop. The heat pump takes the heat from the liquid and transfers it to the air in your home. The cooling process works in reverse; the heat in your home is transferred through the heat pump into the liquid which is then absorbed back into the earth.

  • The heat pump, engineered off of traditional refrigeration compressors, is self-contained, installed indoors and is extremely reliable.

  • The ground loop piping is engineered for a very long life; many manufactures warrant their piping for 50 years.

  • The ground loop piping is joined using thermal fusion (melting the joints together) virtually eliminating any chance of liquid leaks

  • There are less “on” or “off” cycles thus no temperature fluctuations

  • There are no ugly, noisy outdoor condenser units as found in traditional air conditioning

Since geothermal units operate by moving heat, not generating heat, the only energy needed is for moving that heat between the earth and your home. Many geothermal owners find that they have lowered their heating bills by up to 50 percent and their cooling bills by up to 30 percent.


For extra energy savings, you can add a “desuperheater” that connects your geothermal heat pump to your water heater. Unneeded energy from the heat pump is diverted to your water heater which means that in most cases in the summer you’ll be getting nearly free hot water.
Modern geothermal units work extremely well in below zero weather and when the equipment and ground loops are sized properly by your geothermal dealer, electric resistance back up is rarely needed. The geothermal system for your home should be custom designed to account for your local climate and your home’s heating/cooling load.


Geothermal systems are very efficient in Iowa’s climate and work as efficiently as those geothermal systems installed in southern zones.


As with any heating and cooling system, adequate insulation and weatherization are still key factors in lowering energy consumption.

Is geothermal heating and cooling only for homes?

No. Geothermal can be used in nearly any heating or cooling application ranging from large commercial buildings, schools, churches to entire university campuses such as Ball State University.
Geothermal systems have been shown to have competitive installation costs, lower operating and maintenance costs, as well as the lowest life-cycle costs when compared to other systems.

Tell me about ground loops

The loops of plastic piping can be installed either vertically or horizontally depending on the location of your home. The amount of piping needed depends on the size of your home and the loop configuration. Your geothermal contractor will advise you on the best option for your home.

  • Vertical loops: Vertical loops use a bore hole about 4 inches in diameter bored near your home. The depth of the boring(s) depend on the specific needs of your home and what your contractor may encounter during boring. A U-shaped loop of plastic pipe is inserted into the bore hole, followed by sealing with a special grout mixture. Learn More about Vertical loops
  • Horizontal loops: There are a multitude of techniques for placing the loops in the ground ranging from digging a trench about three feet wide and eight feet deep and placing the piping “slinky- style” in the bottom of the trench and covering with soil to using special horizontal boring techniques. Learn More about Horizontal loops