Anybody have experience? I'm planning my next house, and am seriously considering going this route for temperature control. I'm thinking radiant floor heating on the ground floor, and normal forced air HVAC for the rest. I briefly considered hydronic for everything, but I don't think I want to screw around with that. The major brands (Trane, Carrier, etc...) seem to offer hybrid systems, where there's a normal gas or electric backup just in case it gets too cold for the geotherm to keep up. I would choose gas to minimize my electrical requirements (and the size of my backup generator). I'm also looking at having 2 other spaces on the property. A 30x40 shop/garage for projects and toy storage. And another 30x40 "studio apartment" type thing that will serve double duty as guest quarters and photography studio. I'd like these spaces to run off of the same heat well.