This page has a detailed description of water-loop heat pumps, including a diagram, lists of benefits and drawbacks, and links to suppliers. (
http://www.advancedbuildings.org/main_t_heat_water_loop.htm
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This article from the Ottawa Citizen reports on the effectiveness of using ground-source heat pumps in homes. (
http://www.climateark.org/articles/2001/4th/howusehe.htm
)
To learn more about the book this website supports, please visit its Information Center.