Invisible Heating Systems (UK) Ltd.
UK. Design, manufacture and install underfloor heating, geothermal heat pumps, road energy, solar, and wind powered heating systems. Includes technical information, products and contact information.
http://www.invisibleheating.co.uk/

GeoEnergy Solutions Inc.
Provides design and installation of geothermal heating and cooling systems. Also offers sonic drilling for geothermal systems. Based in Bolton, Ontario.
http://www.geoenergy-solutions.com/

TJ's Plumbing and Heating Inc.
TJ’s Radiant Heat Plumbing and Heating provides air conditioning and Snow Melting in Boston Massachusetts and New England
http://www.tjsradiantheat.com/

DOE: Geothermal Energy
Idaho National Laboratory
http://geothermal.id.doe.gov/

Next Energy Solutions
Canada. Specializes in applications of renewable geothermal technology and supply of related equipment as alternatives to conventional heating and cooling systems. Provides detailed background information.
http://www.nextenergysolutions.com/

Energy Commission Geothermal Program
Geothermal Energy in California
http://www.energy.ca.gov/geothermal

Enertran Inc
Canada. Specializes in energy transfer equipment and systems. Includes geothermal heating and cooling units, such as dehumidifiers, drying machines, heat pumps, and heat recovery products.
http://www.enertran.ca

European Geothermal Energy Council (EGEC)
Promotes geothermal energy research and development. Includes news, events, details on joining and board of directors.
http://www.egec.net/

The National Energy Foundation
UK. Useful information relating to water,electric and geothermal based radiant heating
http://www.nef.org.uk/energyadvice/storageheating.htm

International Geothermal Association
Information on geothermal energy in use around the world, world conferences on geothermal, and links to related web sites.
http://iga.igg.cnr.it/index.php