> 2) Ground source heat pumps are complex and very expensive and probably best suited for large installs like schools. Looking at prices for the unit, the diff

> 2) Ground source heat pumps are complex and very expensive and probably best suited for large installs like schools. Looking at prices for the unit, the difference between Ground source heat pumps and air source heat pumps is around 15%. This assume we want heated water. AC-only units are naturally much much cheaper, but since there does not exist ground source AC-only units it is not a very fair comparison. When it comes to extracting heat from the environment there are a few different choices. Air, solar, borehole, ground, and water. As I understand it, which one is the most cost efficient choice depend more on the environment which it is getting installed than the actually unit.