Basement living versus more living space on the ground floor

Only really if it absolutely has to be, because that would involve limitations: it would work if the partial basement were only on the valley side; then it would have to be "accessed" from the side for house connections that are not built over (because with a house connection room on the ground floor, the calculation wouldn’t work out well). On the pipeline side, that would mean paving only the parking space (the one on the other side could have a solid floor or even be a garage). Then I’m curious.

That's how I initially started it: basement on the valley side and HAR in the basement

My suggestion in post #44 assumed that the HAR would then have to be extended/built all the way to the street side due to unbuilt lines. This is actually the ideal solution in such a situation – however, my "thinking error" was treating this as the only possibility. In fact, it is also possible to locate the HAR in a partial basement on the valley side. However, in that case, it is necessary to place it to one side. To avoid building over the lines routed in the side building setback, no garage or covered parking space with a solid floor can be built above them, which would normally be placed in such a location. Instead, one must be content with an uncovered parking space whose paved surface could be easily removed in an emergency. On the other side's building setback, a garage could of course still be built the classic way.

Relatively, exactly.

That's also how I see it: getting the best out of the wishes. And also getting the best and most cost-effective solution even with possible additional costs. I see SplitLevel as the most comfortable solution for that. I have already written reasons for this above. Just post your project with all information about the plot, development plan, etc. in the subforum Floor Plan Planning. Then ambitious people here would also have something tangible to make suggestions about.

So you mean that split level will be cheaper than a partial basement, which is both a utility and living basement and thus also saves additional sheds, etc.?

I thought we had agreed by now that a partial basement is sufficient for you solely for the use as a utility cellar (?), I consider split level unsuitable, as you have explicitly stated that a wheelchair-accessible home for old age is intended; besides, split level is nonsense if the terrain in the area of the house footprint has a height difference of a whole floor.