Hi all – The electricity savings for a ground source geothermal HVAC system are substantial compared to a conventional central AC and furnace setup. But they're less than I expected, so I'm curious where the electricity usage is coming from. I had the impression that ground source geothermal was virtually "free" because it was leveraging the constant temperature underground, and capturing it in the heat transfer fluid. So I figured the fluid pumps would be one source of electricity consumption. So what else is there? The heat pump itself? I guess I don't know how a heat pump works. Is it using the bulk of the electricity? Thanks for your feedback.