[schamp]

I did it with my house in 2002. I have two 3 ton units with about 4000 feet of tubing in the ground on each side of the house. They do work but not a great as we were led to believe. I have added another 2 ton unit and use it just for the master bedroom and master bath. Its works great. Don't max out your system.
I was able to get three 2 ton systems (florida heat pumps, geothermal) at a really good price. I am looking to put these in my shop. I plan on running the geothermal lines down to the lake. Shop is 40 x 60 x 16, insulated, metal. I am hoping 6 tons is enough.
If you put one in, don't forget about you maintenance. When the antifreeze in the lines gets tired, ph drops, and the rust inhibitors wear out, it will absolutely rust out your pump housing. Pumps are expensive.