For years I've been interested in Geothermal units. We bit the bullet and are in the process of having it installed. Last week they drilled three 175 foot wells. This week they bored into our basement with the main line and hooked the three wells together. Next week the Geo unit goes in. It has been fun to watch each step. The best news is we get a 30 percent tax credit and to a 20 percent rebate from our utility company! We are saving 1/2. People ask what our payback will be - well, our old system needed to be upgraded so for almost the cost of a conventional heat system we have Geothermal.