I currently have a heat pump which is approximately 7 years old. Although it works well, I am considering replacing it when the time comes with a geothermal type pump. Anyone have any experience with these units? Is the installation cost prohibitive over regular heat pump equipment? Is there substantial savings by changing to this system? I understand that there is some federal money available for changing to these systems, but is that enough to make it worth it with the new higher SEER ratings of modern equipment?

Yes, the federal tax credit 30% has no limit making geo a nice alternative. Before I told you what the best choice is I need to know. What part of the country? What kind? Ex. Ground loop, open loop, pond loop or vertical loop? Size of house? Water Furnace TM. Has a nice calculator on their web site. Or search for design star. Or maybe an air source heat pump is the better choice. Rheem http://rheem.com/contractorResults.aspx?DesignStar=True&PostalCode=461

Home is approx. 2800 sq.ft, two levels with the lower level being a walkout. Southern Missouri, near Branson on the Arkansas border. Current equipment is a 3 ton heat pump w/ electric heat. No water or pond source available, would have to be a ground loop system.

Geo will probably a slightly better choice.