Geothermal heating is one of my favorite heating and cooling systems. I like the geothermal system because combustion is unnecessary, eliminating the risk of carbon monoxide and other pollutants, there are no fuel tanks or gas lines in the house, very little maintenance is required, it's flexible and can be adapted for forced air or hydronic systems, it and produces both heating and cooling in one unit. The geothermal heating system uses the same technology as your refrigerator. You can learn about how the geothermal system is installed and how it works at this site:

http://www.heating-and-air-conditioning-guide.com/geothermal-heating-system.html

Having a Geothermal Heat Pump System could be the most effective way to achieve a Net Zero Energy home or building and is a major contributor to a zero energy building plan. Net Zero Energy buildings simply are those buildings that produce as much energy as it uses, therefore it is not a net user of energy. Since energy consumption is a major issue, it is imperative to have new methods of keeping usage in check and planning for future consumption needs.

Geothermal Heat Pump Systems take the temperatures found in the layers of the Earth and use them to naturally heat or cool a structure. This drastically reduces the need for straining our energy grids or using unrenewable energy sources. This provides a natural heating and cooling system to help us save our natural resources.

You can retrofit your home if you have a large enough yard space. Installation normally means installing deep wells into the ground along with other equipment such as a heat pump and plastic pipe loops. You need to have a fairly large sized yard and the will to want to have your property dug up! You can contact the U.S. Green Building Council for more information on LEED Certification, which encourages Green Building. Here is a great link for some LEED information:

http://www.usgbc.org/DisplayPage.aspx?CMSPageID=222