Geothermal Heat Pumps | My Home | Mississippi Power | A Southern Company

Geothermal Heat Pumps

Get savings from the ground up with a geothermal heat pump

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Benefits

  • Energy savings - Customers can cut heating and cooling costs in half. Add optional hot water units to save even more.
  • Energy efficiency - Because the ground or water temperatures are much more constant year-round, geothermal heat pumps operate more efficiently;
  • Lower cost - lower operating, maintenance, and life cycle cost
  • Comfort - Constant temperatures are easier to maintain with Geothermal systems. Provide greater comfort than other heating and cooling systems
  • Low maintenance - Fewer mechanical components and no outdoor equipment make repairs less likely.
  • Durability - Closed-loop systems lie underground, protected from harsh weather.
  • Quiet - No outdoor compressor noise. Enjoy your patio, pool or deck without disturbing mechanical noises.
  • Aesthetics - no visible outdoor unit

Highest efficiency available

A Geothermal system takes advantage of the earth's near-constant temperature* to provide the highest energy efficiency for heating and cooling available today. Geothermal closed-loop heating and cooling systems have been at work for more than 10 years with dependable, money-saving and energy-conserving results.

Environmentally friendly

Regardless of whether the outside temperature is 95° or 25°, the ground temperature in cities like Atlanta, Birmingham, Savannah, Panama City or Biloxi is between 65° and 70°. These near-constant ground temperatures make it possible to use the earth's natural thermal qualities to provide energy to heat or cool your home without burning fuel and polluting the environment.

How it Works

Geothermal heat pumps operate like traditional air-to-air heat pumps, moving heat rather than creating heat. However, they use the ground or water as a heat source, rather than outside air, creating an air-to-liquid heat exchange.

The Geothermal system connects an indoor heat pump with a matrix of outdoor buried plastic piping. The system circulates water through these underground pipes where it is warmed by the earth in the winter and cooled by the earth in the summer. This natural heating and cooling action, in conjunction with heat pump technology, can maintain indoor spaces at a constant, comfortable temperature without burning fossil fuels.

Geothermal heat pumps are becoming increasingly popular due to their heating and cooling energy efficiency, and related environmental and ownership benefits, especially where ground water is available or soil conditions are favorable.

In the heating mode, a geothermal heat pump typically extracts two-thirds or more of the needed energy from the earth or water loop and moves it indoors. Only one-third or less of the energy needed is purchased power, primarily used to run the compressor. In the summer, geothermal heat pumps move heat from indoors into the relatively cool earth or water loop. The result in both seasons is that less energy is needed than in conventional, natural gas, air-to-air heat pumps or oil heating systems.

Types of installations

Open Loop — An open loop, ground-water heat pump, uses a surface or underground water source (such as a lake, river, or well) as the heat source. Well water designs are the most common and seem to be the most cost effective. The well supplies both domestic water and water for the heat pump.

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Closed Loop — Closed-loop, ground-coupled systems use a vertical or horizontal heat exchanger buried below the frost line to collect or reject heat. This heat exchanger circulates water in a closed loop to reject or collect heat from the ground, lake, or pond. The water is treated to prevent freezing and to reduce corrosion and scaling. Horizontal heat exchangers need approximately 500 feet of coil for each ton of cooling capacity. Vertical heat exchangers need about 300 feet of underground coil per ton.

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Refrigerant Loop — Refrigerant loops, also called direct expansion systems, circulate refrigerant rather than water, in a buried copper pipe heat exchanger. Direct exchange systems are more efficient and have potentially lower installation costs than closed loop water systems. Copper's high thermal conductivity contributes to the higher efficiency of the system, but heat flow is predominantly limited by the thermal conductivity of the ground, not the pipe.

Questions & answers

What is a Geothermal heat pump?

An electrically powered device that uses the near-constant temperature of the earth to heat and cool your home.

What components make up a Geothermal system?

The heat pump unit, the underground closed-loop system and the ductwork.

What is a closed-loop system?

A continuous loop of special buried plastic pipe connected to the indoor heat pump. Unlike an open-loop system that draws water from a well, a closed-loop system recirculates the same water under pressure, functioning as a heat exchanger with the earth. Because the water is sealed inside the piping, it remains pure, requiring less filtering and less potential maintenance.

How long will the pipe last?

High-density polyethylene pipe properly heat fused should last over 50 years. This material is unaffected by chemicals normally found in soil and has good conducting properties. PVC pipe should not be used.

Can anyone install the system?

Do-it-yourself installation is not recommended. It is best to employ IGSPHA or manufacturer certified technicians and contractors to install your Geothermal system. Retrofits in buildings with existing ductwork are typically easy to install. Consult your local dealer to determine any modifications that might be necessary.

What if I need heating but have no ventilation?

Geothermal uses no combustion and therefore needs no outside venting.

How effective is this underground system?

Conceived in the 1940s, refined heat pump designs and improved pipe materials make Geothermal systems the most efficient heating and cooling options available today.

Will the buried pipes affect my lawn or landscape?

After installation, closed-loop piping has no effect on grass, trees and shrubs. Installation requires displacement of some turf which can be restored with grass seed or sod.

Can a Geothermal system also heat water for my house?

Yes. Using a device called a "desuperheater," Geothermal systems can preheat tank water to save up to 50% on water heating bills.

For more on Geothermal heating and cooling systems, visit these websites:

*Look for Geothermal in Georgia, Alabama, Mississippi, and Florida, where ground temperature does not fall below 60° F.

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