I noticed that under the System tab in the web page you have Geothermal. however, you do not mentioned Direct exchange systems. I would like to know more about them and your opinion of them regarding energy savings when installing such systems.
I have no direct (haha!) experience with them myself but I have heard others experiences and it's made me kind of leery of them. How long will copper last in the ground compared to plastic? Apparently many years under the right soil conditions. Sure they are a tad more efficient than a conventional set up but that's an awful lot of refrigerant you need to fill it up, $$ on start up & $$$ for service if you get a leak. There has been quite a bit of talk on the geoexchange.org forums in the past on DX systems, have a search on there to get some dirt (haha!)
Reminds me of the solar hw systems of the 1970's Alot of people with limited hvacr experience installing these systems. I worked on 1 that utilized a well system, the refrig. systems would trip on high head press. when the grout material in the wells was dry, worked ok when the ground around the well area was moist, after it rained. proper design and install is crucial.