Renewable Energy : Geothermal

Geothermal energy uses the heat from the Earth to provide power, heat water, and heat and cool buildings. Avoiding the use of nonrenewable, geothermal energy is clean and sustainable.

The shallow ground of the Earth's crust maintains a nearly constant temperature between 50° and 60°F. In the winter, the earth's ground temperature is warmer than the air , and in the summer, the ground temperature is much cooler than the air. Thus, this upper 10 feet of the Earth's crust can be used to heat and cool buildings!

In residential buildings, geothermal energy is frequently harnessed using geothermal heat pumps. By tapping into this shallow ground, the geothermal heat pumps tap use these constant temperatures of the Earth's surface as a resource to heat and cool buildings.

Geothermal Downtown!

One of the biggest concerns with the installation of geothermal systems is the fact that it can take a sizable amount of space to install. In downtown Charleston this may be an issue at times, but it is possible. Even a small side lawn can suffice for installation of geothermal, as shown in the image to the left of the property on Ashe Street! The picture to the right also shows the minimal equipment requried. The ductwork is stored in the attic of this single house.

How it works

Residential geothermal heat pump system typically consist of three major components: the heat pump, an air delivery system (ductwork), and a system of pipes buried in the shallow ground near the building, Refered to as the heat exchanger, this system of pipes is filled with fluid, usually water or a mixture of water and antifreeze. As this fluid circulates through the pipes, its temperature adjust to the moderate temperatures of the earth.

In the winter, when the earth's ground temperature is warmer than the air , the heat exhanger collects heat from the ground. The heat pump moves this heat from the exchanger and pumps it into the air delivery system, moving it inside the house. The air delivery system is usually placed in the basement of the house.

In the summer, when the ground temperature is much cooler than the air, the process is reversed. The heat pump moves warm air from inside the home into the heat exchanger. Here, the ground with its constant temperatures, cools the warm air in the exchanger system.

An extra perk to geothermal systems is that they can also provide domestic hot water. In the summer, the heat removed from indoor air can provide the source of heat for hot water supplies.

"Geothermal heat pumps use much less energy than conventional heating systems, since they draw heat from the ground. They are also more efficient when cooling your home. Not only does this save energy and money, it reduces air pollution."

Visit for information on Federal and State incentives for Geothermal!

This house on Ashe Street has a geothermal system installed to provide their heating and cooling loads and also domestic hot water.