Multifamily house - Building savings contract & pre-financing sensible?

Where in NRW is "in town"? Then a brine-water heat pump is certainly more than worth a look. nordanney has already given the right tip for this. It honors you that you want to create affordable housing; in my opinion, you don’t create a good living/rental community just through the low cold rent per sqm. You also only look at every person superficially ;)

Town = Unna (for all those who don’t know the gateway to the Ruhr area: almost 60,000 inhabitants, directly east of Dortmund, famous for the traffic jams on the A1/A2 at the Kamener Kreuz and the A44. Of course, there’s a bit more there. ;-) ) The district used to have (over 100 years ago) a spa with salt brine and so on and generally mining in the region. I just know that when my parents built their house back then, they also had to coordinate that with the relevant authorities... I will take a look at a brine-water heat pump. Basically, we have some people in our circle of acquaintances who would like to live in such a house, which is why I already know them a bit and am quite optimistic that I can put together a reasonably decent house community.