Sanitary shell inspection: What should we pay attention to?

I would not go below 20. Reasons: - Conversion of the space - Possible cooling through the floor - Possible "short circuits" due to too short circuit lengths 20cm everywhere and 10cm in the bathroom is already a compromise. Further compromises would then bring little joy.

We have spoken with our site manager. He understands the issue with the bathrooms and wants to enforce a closer installation of the sanitary fixtures in these two rooms. Just as you suggested. In between, (once again) a heartfelt thank you for sharing your expertise. :)

Just a quick question: Isn't this the typical necessary approach in developer projects with lazy and/or incompetent MEP planners/plumbers? So in the bathroom the installation spacing is kept as small as possible and everywhere else so that it fits reasonably well?

I can 100% confirm that impression. :D Our plumbing company serves, in addition to our small general contractor, a large prefabricated house provider and is currently building a larger hall.

A quick side question: Isn’t that the typical necessary approach in developer projects with lazy and/or incompetent MEP planners/plumbers? So, in the bathroom the installation spacing is as small as possible, and everywhere else it's adjusted to fit reasonably?

Yep. Plus a "We always use this WP" and everywhere becomes nicely and comfortably warm. Whether efficient or not doesn’t concern the general contractor.

Note to everyone: I assumed from the term "Summary of the quick design" that the final and efficient design would still follow. What the heating installer did was produce a design with three clicks using a simple program. It didn’t cost anything – but it’s enough for cost calculation. The correct design by an MEP planner/engineering office then takes a few days and costs about €150. That’s how the process should be. That way, in the end, you also get a proper bathroom.

What the heating engineer did is produce a finished design with three clicks using a simple program. It cost nothing - but is sufficient for a cost calculation. That’s how the procedure should be. Then, in the end, you also have a correct bathroom.

I will also give this as final feedback to our general contractor regarding this trade. Until then, I am glad that we at least get a suitable heat pump and not just one that is currently available, and hopefully more closely laid children's bathrooms.