immac

Although it sounds high, it really depends on the size of the house/system and the comparable cost of heating and air-cooling systems.
In USA, these systems are typically 30% more than a standard system installation and would recoup the extra investment over 10 years. If the pump is run by solar electric, the savings are higher. The main savings would be seen in low monthly energy costs. Also, a ground loop rather than deep bore hole can lower installation cost.

Ian