GeoExchange General Questions
What is geoexchange technology? Geoexchange technology uses the earth's renewable energy, just below the surface, to heat or cool a home or other building, and to help provide hot water.
How does it work?A few feet beneath the surface, the earth's temperature remains fairly constant -ranging from 7º or so in Canada's northern latitudes to about 20ºC in the US deep south -year round. Geoexchange takes advantage of this constant temperature to provide extremely efficient heating and cooling.
In winter, a water solution circulating through pipes buried in the ground absorbs heat from the earth and carries it into the home. The Geoexchange system inside the home uses a heat pump to concentrate the earth's thermal energy and then to transfer it to air circulated through standard ductwork to fill the interior space with warmth.
In the summer, the process is reversed: heat is extracted from the air in the house and transferred through the heat pump to the ground loop piping. The water solution in the ground loop then carries the excess heat back to the earth. The only external energy needed for Geoexchange is the small amount of electricity needed to operate the ground loop pump and fan. It is more efficient and environmentally superior to 'transfer' heat than to 'create' it through combustion.
Is Geoexchange new? Not really. The basic technology has been around for more than 30 years, and many homeowners and businesses have been enjoying the benefits of Geoexchange for much of that time.
In recent years, though, many improvements have been made in the materials used, the installation methods, and the efficiencies of the compressors, pumps and other equipment.
What are the major benefits to the homeowner? Homeowners enjoy lower utility bills (25% to 50% lower than with conventional systems), lower maintenance, and higher levels of comfort, year-round. Even more than that, though, they have the peace of mind of knowing they're being environmentally responsible.
Since a geoexchange system burns no fossil fuel to produce heat, it generates far fewer greenhouse gas emissions than a conventional furnace, and completely eliminates a potential source of poisonous carbon monoxide within the home. Even factoring in its share of the emissions from the power plant that produces electricity to operate the geoexchange system, total emissions are far lower than for conventional systems.
Can you be more specific about the environmental advantages? If geoexchange system were installed in 2% of the single detached houses in Canada, this would be the equivalent of taking over 100 000 cars off the roads and save about 375 K tons CO2 equivalent emissions per year.
And the waste heat removed from the home's interior during the cooling season can be used to provide virtually free hot water-resulting in a additional savings in hot water costs of about 30% annually, and lowering emissions even further.
Is geoexchange 'Kyoto-compliant' 'Kyoto-friendly' or a 'green' technology? Installing geoexchange and enormously reducing your consumer electricity and heating bills, needs, and usage, are very helpful in helping Canada meet our national energy policy goals regarding Kyoto. In that sense, geoexchange is a very Kyoto-friendly technology.
Geoexchange systems are indeed officially classified by Natural Resources Canada as a 'renewable' energy, meaning that they operate without destroying finite natural resources. In practise, geoexchange is usually paired with conventional electricity generation, which uses some fossil fuel (though up to 80% less than a conventional system) to run system heat pumps. CGC members and member installers will be pleased to discuss and/or help you plan a fully 100% renewable system, though costs may be higher.
Is geoexchange used primarily in homes? Perhaps surprisingly, no. While many homes have been fitted with geoexchange systems, commercial enterprises, including factories, retail stores, office buildings and schools are the biggest users of geoexchange to save energy and protect the environment.
What about a very cold climate-does geoexchange work well?Yes, geoexchange technology can be used in any part of the country. Why? Because it transfers heat to and from the earth, which remains at a relatively constant temperature, rather than the air, where temperatures can vary greatly.
Does geoexchange cost more? That depends on when you measure cost. While geoexchange costs more to install in homes than conventional systems, because of the ground loop piping, geoexchange systems typically have the lowest life-cycle cost of any heating and cooling system.
Moreover, installation costs have declined substantially in recent years, and they're expected to continue to fall, as more builders and contractors offer geoexchange systems, and as the industry develops innovative ways to install the systems faster and more efficiently.
Altogether, geoexchange systems are a very sound investment. The amount they save the homeowner every month in energy costs is more than enough to offset their higher installation cost.
Remembering that geoexchange also means extra savings on repair, maintenance, and hot water bills, the energy efficiency of geoexchange adds value to your building whether home, apartment building, condo, skyscraper, or sports stadium.