How Geothermal Works

Basically, geothermal heating/cooling systems operate via sub-surface conductive heat transfer, using the naturally renewable temperature of the earth’s crust as a heat source in the winter, and as a heat sink in the summer.

Cooling Mode Operation

In the cooling mode, the hot refrigerant (well over 100 degrees F) exiting ETA’s compressor is sent directly into the approximate 50 to 60 degree F range deep earth, which now absorbs and takes the heat away. The cooled refrigerant fluid is then circulated through the air handler where it absorbs and removes unwanted heat from the interior air. The heated refrigerant travels to the ETA system’s compressor unit where the process is repeated. Thus, in the cooling mode, the ground removes your heat for free.

Heating Mode Operation

In the heating mode, approximate 50 to 60 degree F range naturally occurring heat from deep within the earth travels to, and is absorbed by, a much colder refrigerant fluid that is circulated within the copper tubing inside a deep well/borehole. Such naturally occurring heat is transported by the refrigerant fluid to the system’s compressor where the fluid is compressed, thereby raising its pressure and temperature, transforming the 55 degree F temperature into a temperature well over 100 degrees F. The hot refrigerant is then circulated through the finned tubing within an air handler, where the cold return interior air absorbs the heat. The heated air is supplied, via a fan, to the interior air space. With the heat now removed from the refrigerant fluid, it becomes very cold and is re-circulated into the ground to absorb more naturally occurring and renewable heat. Thus, the ground supplies your heat for free.

Hot Water Heating

Utilizing the ETA geothermal system’s optional Hot Water Pre-Heater (HWPH), the system can also produce virtually free hot water. Capturing excess heat in the refrigerant, this module can typically provide about 50% of the total hot water needs for an average home or business. Additionally, the ETA system can be designed to solely provide heat for low-cost hot water generation for hot tubs, swimming pools, or for in-floor hydronic heating purposes.

ETA units can be specifically designed to solely heat water for residential, commercial, and industrial applications at a fraction of the cost of conventional methods.

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Geothermal for the Home

Geothermal home heating systems, also known as ground source heat pumps, is a system that transfers the temperature from the ground to your home.

It uses stored solar energy from the ground beneath to provide energy for heating and hot water. Though the term Geothermal heating, as it is frequently referred to, sounds as though it uses hot rock energy it is, in most cases, stored solar energy.

In winter the heat pump collects the Earth’s natural heat through pipes, called a loop, and installed below the surface of the ground or submersed in a pond or lake. Fluid circulating through the loop carries the heat to your home. There, a compressor and a heat exchanger, driven by electricity, concentrate the Earth’s heat and release it inside the home at a higher temperature. The heat is carried to different rooms by ductwork.

The process is reversed in the summer. The underground loop draws excess heat from your home so it can be absorbed by the Earth, using it as a heat sink. The system cools your home just as a refrigerator keeps your food cool – by pulling heat from the interior, not by blowing in cold air.

Your geothermal heat pump can be either vertical or horizontal. In a vertical system the pipes may go to a depth of up to 650 feet.. this will minimize the amount of land surface required and keep disruption to a minimum.

Vertical coils are ideal for installation where space is limited, fitted to a depth of up to 200 metres minimising the land required on the surface, keeping disruption to a minimum.

The loop can be closed or open and horizontal or vertical.

An open loop system uses two wells. It draws water from one, passes it through the heat exchanger and then discharges the water into the second well. It takes about two or three gallons a minute per ton of capacity for effective heat exchange.

A closed loop system uses water, or a water/antifreeze solution to collect or distribute the heat.

A closed loop horizontal geothermal heat installation involves burying pipes in trenches. A closed loop vertical system uses a U-tube installed in a well drilled 100 to 400 feet deep

A third closed loop type is a pond closed loop. Closed loop coils can be placed on the bottom of a pond or stream with enough depth and flow. Fluid is pumped in the same way as a closed loop ground system. The economics of This geothermal heat system is very economical, and without impact on the pond.

A geothermal home heating system makes sense because:


  • It uses a completely free and renewable source of energy
  • It works with and not against nature and has virtually no environmental impact
  • CO2 emissions are reduces
  • Low maintenance costs are low
  • Geothermal home heating systems add value to property
  • Compatible with most modern heating systems – ideal for under floor heating
  • You get up to 70% fuel bill savings
  • Easy to use


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