Like a cave, ground temperature is warmer than the air above it during the winter and cooler than air above it in summer.
While many parts of the country experience seasonal temperature extremes—from scorching heat in the summer to sub-zero cold in the winter—a few feet below the earth's surface the ground remains at a relatively constant temperature. Depending on latitude, ground temperatures range from 45°F (7°C) to 75°F (21°C).
Like a cave, this ground temperature is warmer than the air above it during the winter and cooler than the air in the summer. Geothermal technology takes advantage of this by exchanging heat with the earth through a ground heat exchanger. As with any heat pump, geothermal and water-source heat pumps are able to heat, cool, and, if so equipped, supply the house with hot water.
Even though the installation price of a geothermal system can be several times that of an air-source system of the same heating and cooling capacity, the additional costs are returned to you in energy savings normally within 5–10 years. System life is estimated at 25 years for the inside components and 50+ years for the ground loop. There are approximately 50,000 geothermal heat pumps installed in the U.S. each year.
To review additional water heating options, click any of the following technologies: Tankless (On-Demand) Hot Water Heaters, Solar Water Heaters, High Efficiency Gas Storage Water Heaters, and Indirect Water Heaters