About Geothermal Heating & Cooling and Geothermal Technology - How It Works Your own backyard has the potential to be an energy source for heating and cooling comfort. Outdoor air temperatures fluctuate throughout the year with the changing seasons. In contrast, ground temperatures about four to six feet below the Earth's surface remain relatively moderate and constant all year.

That's because the Earth absorbs 47% of all the heat energy that reaches its surface from the sun. A geothermal system circulates a water-based solution through a buried loop system to take advantage of these constant temperatures. A single piece of equipment has the ability to heat and cool your home, while providing some or all of your home's hot water as well. Geothermal systems can save you 30% to 70% on your monthly utility bills.

Geothermal is the safest, cleanest, most reliable space conditioning system you can buy. Geothermal energy is an unlimited resource. The lot surrounding a suburban home or other building contains a vast reservoir of low temperature thermal energy, typically 10 times that required over an entire heating season. This resource is constantly resupplied by the sun, the surrounding earth, and heat rejected while cooling during the summer. The universal definition of geothermal is "...pertaining to the heat of the earth." By using the earth to provide up to 50% of a building's total heating and cooling needs, GHP systems are truly geothermal energy made practical.

Four basic types of geothermal energy sources: Closed loop systems circulate a water-based solution through a "loop" of small diameter, underground pipes. In cold weather this solution absorbs heat from the earth and carries it to the geothermal unit. The geothermal system amplifies the heat and delivers it indoors. In warm weather the process is reversed, excess heat is carried from indoors and into the earth. You keep refreshingly cool during the hottest summer. The three types of closed loops are horizontal, vertical, and pond:

	Horizontal loops are often considered when adequate land surface is available. Pipes are placed in trenches, in lengths that range from 100 to 400 feet.
	Vertical loops are the ideal choice when available land surface is limited. Drilling equipment is used to bore small-diameter holes from 75 to 300 feet deep.
	Pond (lake) loops are very economical to install when a body of water is available, because excavation costs are virtually eliminated. Coils of pipe are simply placed on the bottom of the pond or lake.
	Open loop systems are the fourth type and utilize ground water as a direct energy source. In ideal conditions, an dopen loop application can be the most economical type of geothermal system.