Floor plan of a small single-family house on a north slope 170m²

First of all, many thanks ypg for your effort and your great suggestions! I’m really impressed. Yes, you’re right that it is practically placed in front of the slope and then you have to pile up the rest. I still have to figure out the costs myself...

let’s take a basement anteroom of over 20 sqm, what is it used for? Basically, of course, for openness and access to the garden. But in my opinion, you can’t afford that. What kind of gym room is that?

Yes, the anteroom in the basement is practically hallway space and that is where the greatest need for optimization exists (I have already heard that from several sides). The gym room would be for me because I am very athletic and would like to have that “luxury” - if possible, but of course not a must...

supposed to. This door (in the basement) will probably be very frequently used, considering that it is the most convenient way to the garden

Yes, you’re right and up to now I only considered the upper floor...
Shifting the staircase approach more into the center is a good idea so that everything feels more homely

Regarding the further floor plan: in my opinion, the flood of doors in the parents’ area just doesn’t work. The two bathroom doors will cause problems: they obstruct each other.

You implemented that well in your suggestions and I will probably adopt that idea!

South-facing windows are important, but you can rarely really enjoy a south terrace. Also, there is a street here, so you wouldn’t exactly look for the calm you find in the back garden area, which is also sunny.
Therefore, as a layman, I would forgo a south terrace, rather place it with a slope/hill to the west and then have access to the garden.

So if I understand correctly, you would rather shift the house towards the south and focus entirely on the back garden? Would west-facing windows be sufficient in this case, in your opinion?

It is planned to be connected with the master bathroom through glass doors, which can be frosted if you don’t like that. This creates a retreat on a small area. Maybe that’s a suggestion for the next experiments...

Definitely that, and it will be included in the next plan!

Yes, while modeling I realized for myself that both floors would benefit if the stairs (more of a two-flight with more openness and not one with a basement character) were planned elsewhere. And the kitchen or dining table where you approach.

Yes, that can be tried! I definitely wanted the couch to be oriented to the north because that’s where the view is and we do spend more time on the couch than at the dining table anyway.

So if I understand correctly, you would rather move the house towards the south and put the entire focus on the backyard?

I don’t know what you mean.
You can’t really talk about moving it, since no one here knows what kind of slope this is. In your 3D version it looks steeper than a dike, and your sketch doesn’t provide any measurements for the depths, meaning the distances to the slope.
Only if you put the house IN FRONT of the slope do you need even more soil, of which you actually already have too much.
That’s what I meant by “get an architect involved.”
Regarding the garden: living in summer or good weather is simply about the garden. Not necessarily sitting in the neat chill lounge, but watering, weeding, designing, planting, and enjoying garden spaces. With kids at the paddling pool, on the swing, in the sandbox, or on the lawn. In the evening you go to the terrace to have dinner. Once the kids are in bed, then you sit on the sofa outdoors or indoors. When my husband and I watch TV, we go outside during every commercial break because there’s always something to do. Ok, there is water automation for that... but what I want to say is: you enjoy and live the garden if you want to have one.

Would west-facing windows be sufficient in this case, in your opinion?

For me personally, no. I need the sun inside the house in winter, and that I don’t get from west-facing windows. But everyone may have different preferences. If you are aiming at the basement or ground floor: I would see my living space down there like . Many large north windows. However, upstairs I would set up a relaxation zone with southern sun for the winter. The last six weeks of last year had four sunny days. I would then spend those days on a sunny gallery with books or knitting or something. :)

I definitely wanted the couch oriented towards the north because that is where the view is, and we do sit more on the couch than at the dining table.

Even with children? Hm... the real question now is whether you are prepared for kids. We also sit on the couch a lot, but don’t have kids. But activities just don’t take place on the couch. Do you live in an apartment now? Life definitely changes in a house.

Basement feeling fits well. This is not the design of a house that uses all areas and floors. This is an apartment with an added basement.

Take Ypg's advice to heart