for the simple water pump into the earth you need a floor heating system.
and this makes it expensive.
its only profitable if the flyback in your heating system is very cool.
because of this you only get high energy earning numbers if you do have a "floor heating system. "
my families house for example do have a floor heating system but we already do have a power plant.
and a power plant beat a heat pump all the time.
because heat is cheap in Germany and electric energy is expensive.
we just do have a educational problem most people don't know anything about "heat-pump" and stuff.
in germany the KFW pay money for your project if you use a heat-pump-system but only if you also do have a "floor heating system." because they think it only works if you do it right with an floor heating system.