How it Works

Geothermal heating and cooling systems use the natural and nearly constant temperature of the earth to heat in the winter and cool in the summer. This is accomplished with a compressor or heat pump unit, the liquid heat exchanger medium, and the air delivery system.

Geothermal systems quite simply extract heat from the ground or ground water and transfer that heat to a refrigerant, then distribute the heat into the structure with a forced-air or hydronic system. In cooling, geothermal systems take heat from the structure, transfer the heat to the refrigerant, then transfer the heat back to the water or loop fluid. This works the same as a standard air conditioner, except a geothermal system uses water or loop fluid at a constant temperature (average 50 degrees) instead of varying outdoor air.


In other words, it’s like heating and cooling your home when it’s 50 degrees outside – all year!

Open Loop

Open loop geothermal systems use water from a well

If there is sufficient water quantity and water quality, the home’s water well can provide the water for both domestic household purposes as well as for the geothermal system. There will be a discharge of water to a drain, ditch, stream or pond.

Well water is pumped from the pressure tank to the geothermal unit, heat is extracted from it (heating) or added to it (cooling). There is no contamination or change to the water. Geothermal systems require 1.5 to 2 gallons per minute per ton of capacity. Most homes will use between 5-8 gallons per minute whenever the geothermal system is operating. Because the home’s water well can serve a dual purpose, an open loop system can provide the lowest installation cost for a geothermal system.

Closed Loop

A Heat Exchanger within the Ground

Closed loop geothermal systems utilize a series of piping buried in the ground  or submerged in a pond to create a heat exchanger. This piping is filled with a water/antifreeze solution (loop solution) that allows the geothermal system to take advantage of the constant temperatures stored in the earth or pond.  There are several types of systems.  Horizontal, Pond & Vertical.

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Open vs Closed - Q&A

Which system is better for my home, open loop or closed loop?

That depends on a number of factors… your budget, the availability of an adequate water supply and discharge, yard space, and most importantly your own preference.


How does the cost of operating an open loop system compare with a closed loop system?

An open loop system has an average water temperature of 52 degrees and uses the water well pump to deliver the water to the unit. A closed loop system averages 40 degrees in the winter, 70 degrees in the summer, and uses a small dedicated circulating pump. Factoring in these minor differences, the cost of operation is nearly the same.

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