[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.