The earth absorbs energy from the sun and stores it in the ground. A geothermal system extracts that energy for home heating during the winter.  For cooling, the system removes heat from the home and places it into the cooler earth. This transfer of heat energy is done through a series of pipes either in the ground, sunk in a pond, or by using well water. 

Renewable Energy From the Earth

Geothermal systems are renewable energy from the earth, so the technology is one that can reduce your carbon footprint. On a grander scale, imagine the impact of the reduced emissions resulting from every current geothermal comfort system installation today. The collective result would be a dramatic reduction in carbon footprint. 

source: Bryant Geothermal Comfort Systems Consumer Brochure 

Horizontal Loops

Used on larger lots. They are installed using a backhoe or a trencher. Taking up more land area than any other loop type, they are used where space permits. Trenches are normally 5 feet deep. Normally, several hundred feet of trench is required.

 
Vertical Loops

Used where land are is limited or soil conditions prohibit horizontal loops. Installed using a drilling rig. 

Pond Loops

Coils of pipe are connected and sunk to the bottom of the pond.

 
Open Loops

Well water from an existing well can be used, then discharged into a drainage ditch or pond.