I found this:
1: Why are Geothermal Systems so expensive?
Answer: The equipment costs close to the same as a quality name brand high efficiency furnace and air conditioner. The additional cost involves the installation. An open loop usually requires less capital investment than a closed loop system if the well and discharge are already existing.
A horizontal loop requires excavation equipment and pipe installation.
A vertical loop requires drilling and excavation equipment and pipe installation.
Special tools are required to fuse the plastic pipe together underground.
Special flushing and charging equipment is required to clean, air purge and freeze protect the earth loop once it is connected to the geothermal unit.
Ductwork is somewhat larger than with other furnaces because geothermal systems move about 40% more air than fossil fuel systems of similar heating capacity.
