On: The humble water heater could be the savior of our...

[sidewndr46]

I don't know anything about Iceland but I am using the definition from energy.gov

https://www.energy.gov/energysaver/heat-and-cool/heat-pump-s...

Geothermal works with either vertical holes in the ground or a big loop spread out horizontally. Neither one is very deep nor does it involve hot rocks.

[scotty79 → sidewndr46]

Ah, geothermal heat pumps is perfectly accurate.

Geothermal heat on the other hand is a wider term https://en.m.wikipedia.org/wiki/Geothermal_heating of which geothermal heat pumps (ground source heat pumps) https://en.m.wikipedia.org/wiki/Ground_source_heat_pump are just a subset.