What is Geothermal Energy?

Most people don't realize that geothermal heating is actually a solar technology. You can see from the diagram at the right that on average 46% of the solar radiation striking our planet is absorbed by the earth. Just think about it -- if the solar energy was not absorbed, then the temperature of the earth would be like at the north and south poles -- VERY cold.

Instead, the temperature of the earth at every location is a direct function of how much solar energy does strike the earth. This has been studied in depth, and you can see from the diagram below what the average temperature of the earth is at your location. In the Asheville, NC area, the ground temperature is about 59ºF.

Earth Temperatures in the US

Geothermal heating and cooling gets its excellent efficiency from using the earth as a thermal anchor. You can see from the chart at the left what the average ground temperature is in your location. This means that the ground is approximately the temperature shown which is way warmer than the air in the winter time, and is way cooler than the air in the summer. This is the basis of the efficiency of the geothermal heat pump system.

High Temperature Geothermal

There is another energy source also called "Geothermal Energy" which involves the use of very high temperatures in areas near volcanic activity. This use of "high temperature" geothermal energy is currently being implemented in the western portion of the US, and shows some promiss toward generating large amounts of electricity. But, this "high temperature" geothermal energy has nothing to do with heating and cooling a house or business. Asheville Geothermal is solely focused on the geothermal energy available from the sun's heat occuring in the outer crust of the earth that can be used for heating and cooling.

Great Geothermal Video

Here is a short but very good video that adds good perspective about the soundness of a GHP system investment. The video depicts two homes in Stillwater, OK where the modern GHP systems were started. One of the systems shown has been in continuous use for 35 years.