Space and cost for geothermal heat pump

With 11,000 euros do you mean the entire heating installation or just the device? Your drilling was not without cost either...

Yes, including all pressure vessels, installation, commissioning. The drilling was unfortunately expensive – more or less a monopoly with the W-120-2 certificate (from those who still had capacity at all). We searched in vain for someone with experience in trench collectors.

It's a bit late, but you could have definitely dared to do it. We realized it ourselves and it worked without any problems. Much better than I expected with my two left hands...

The second house is better