if you install a closed loop system. In a closed loop system, you are only expending energy moving water through the pipes. Imagine you are holding both ends of a garden hose with water in it. If you add water to one end of the hose, the water at the other end will naturally...
Utilizes renewable energy: the steady temperature of the earth. One of the most efficient HVAC systems for supplying heating, cooling and (with some systems) hot water. More efficient than air-source heat pumps. More efficient than electric resistance heating. ...