[nagisa]

Out of curiosity, why did they think 50kW was a necessary amount of energy to heat? Is the building old and poorly insulated? An A/A+ energy class 150m² home barely needs 1/10th that amount.

If it was indeed a question of insulation or airtightness, then perhaps spending a part of that money for renovations in that area and only then a fraction of the price for a reasonably-sized heating unit might be sensible. You could also do just the renovations and thus reduce your wood pellet usage substantially as well – already a big win for the environment.

[c2h5oh]

Almost 800 m^2, 55cm thick red brick walls with OK, but not great insulation, casement windows.

That aside what I wanted to point out is that because of heat pump pricing they are currently not the best choice, economically speaking. It is 6-10x more expensive upfront and won't break even over it's lifetime.

By comparison solar panels break even is 6-8 years and after that they are expected to last 20 more years bringing you 2-3x installation costs in savings over their lifetime.