[thayne]

It seems like a bidirectional heat pump would be a good solution, since the same device can be used to heat the building when it's cold. And a lot of europe (including the mentioned UK and Greece) don't often get cold enough that a heat pump is inefficient.

[msh]

The uk gets cold enough that a air to water heatpump is a better heating solution.

[fancyfredbot]

Air to water heat pumps are typically less efficient than air to air. Both will work in cold UK temperatures. However the water is often heated to a higher temperature which can reduce efficiency.