A geothermal heat pump (GHP) uses the constant temperature of the earth, instead of the outside air, to exchange heat with the earth using a ground heat exchanger. Instead of using oil, propane or gas to heat homes and other buildings, a geothermal system uses that constant earth temperature to move heat and cool.
Outdoor temperatures fluctuate, but five feet (or 1.5 meters) below the earth, ground temperatures remain constant – even in winter – at around 10°C (50°F). This ground temperature is warmer than the air above during the winter and cooler in the summer. A GHP takes advantage of this by exchanging heat with the earth through a ground heat exchanger.
A geothermal system is installed by pumping an environmentally-friendly fluid through horizontal or vertical underground pipes (closed loop). In the winter, the fluid absorbs the heat from the ground and, now warmed up, transfers it to the heat pump in your home. The heat absorbed by the fluid from the solar-heated ground is extracted from it by the heat pump, and the now-chilled fluid is circulated through a heat exchanger over and over again to extract more heat from the earth.
In the summer, the heat transfer process is reversed. The fluid in the pipes leaves the house in a warm state, but after circulating underground, is cooled as the pipes exchange heat with the cooler earth.
Why should I buy a geothermal system?
One reason is the tremendous savings on your energy bill. Annual heating bills can be reduced by up to 70 per cent. Because geothermal energy is always available in the earth and doesn't need to be shipped a long way, you are not affected by changing or unpredictable prices. What other benefits are there?
In surveys, homeowners routinely rank their geothermal systems "more comfortable" than traditional heating systems. In winter, there's a constant flow of warm air throughout your home, eliminating hot or cold spots. In the summer, the heat pump removes humidity; you can set your thermostat to a higher temperature but it actually feels more comfortable because there's no humidity anywhere, including the basement – no more dampness.
Geothermal is quiet
There's no combustion or forced-flame noise. In winter, geothermal pumps quietly circulate fluid through the heat exchanger. The need for a separate outside air conditioning unit is eliminated, so your backyard or patio remains peaceful.
Geothermal is safe
Geothermal produces no flame, no chimney, no flue and no dangerous fumes such as carbon monoxide.
Monthly cleaning of the electrostatic filter once a month is all that's needed to keep the system running smoothly.
Geothermal units have a life expectancy of 25 years.
1 Source: Quest Geothermal