Underfloor heating air-water heat pump. House too warm when the sun shines

Unlike the OP, I am glad to have every ray of sunshine in the house during winter. This way, I have to spend less money on other energy sources. But if you follow the advice given here and optimize the heating system, it will surely be similar for the OP.

Uh... and all the likes.... You probably ended up with your answer in the wrong thread.
This is not about a floor plan, this is about heat generation through south-facing windows in the existing building.

It is already clear that this is not a floor plan issue and that the house is standing.
Perhaps such scenarios were not extensively considered during the floor plan design or other conditions led to this.
Anyway, the OP is describing a problem, and what they received is a proposed solution based on the given conditions.

The OP can surely best judge whether this is a suitable suggestion/food for thought that fits the topic!

we also have something like that - I have the windows cleaned 2-3 times a year anyway, they then do the roof as well.

That's exactly how I do it too You can easily walk on the glass.

To come back to the original topic once again:

A south-facing orientation with a view and sunlight is quite nice, but it also brings some challenges. "Where there is light, there is also shadow" – fits quite well here.

But I also see other things coming your way:

[*]In summer, you will be roasted without shading (outside) or stewed (inside). Or sitting inside with artificial light in the best sunshine
[*]You should think carefully about having a terrace in the basement in front of the bedroom window. On the one hand, the living area is on the ground floor, so presumably also the kitchen, dishes, etc., which would mean carrying things up and down the house to enjoy the terrace. On the other hand, guests can constantly look into your bedroom, or it seems to be the shortest way to get into the house, probably also for guests. Personally, I would have difficulties with that...

Here is an idea to have a combined solution for the various challenges (at least for me and as long as I have not misunderstood your floor plan).
The terrace is built on stilts/poles, approximately at the height of the left extension, possibly with stairs to the garden. Above that is an awning or a roof. Such a construction, of course, in a "nice" design.

[*]You can go outside from the living area without changing floors
[*]No one can look into your bedroom
[*]Shading above and below
[*]Still free views of greenery above and below

With the south orientation, the hillside location, and the chosen layout, certainly an exciting challenge

Hi, thanks for your ideas. The view into the bedroom is prevented by curtains. We have planned a refrigerator and a sideboard with dishes downstairs, so you don’t always have to run upstairs. The construction you suggested is certainly good, but also surely expensive. I will have to propose that to my husband.

through curtains

Uahhh, that still exists???
Jokes aside - that wouldn’t have been the optimal layout for me either, but you must have had your reasons.

We have venetian blinds combined with automatic control that adjusts according to lux (i.e. light incidence) and indoor temperature. So in winter, they only go down when it’s over 24°C inside (yes, we both prefer it cozy).

Originally, we wanted the venetian blinds in the color of our window frames (which is called Eta, a kind of grayish brown), but the window manufacturer strongly recommended aluminum venetian blinds and we are very thankful for that now.
The automatic control is set so that the venetian blinds don’t stay completely closed, but are half open. We still have plenty of light even when they are down. You can still see outside – of course with stripes in the view, but a panoramic view is still possible.
Because of the light aluminum and a special shape of the slats, light is guided into the house while heat stays outside.
We are very satisfied with this solution, and in summer, when the shading was finally installed, the house always stayed pleasantly cool even when it was over 30°C outside every day. That’s one of the great things about modern, highly insulated houses: if you don’t let it get too hot inside at all, the heat stays outside!

That's exactly how I do it too You simply can't walk around on the glass without any problems.

Isn't a "not" missing there?