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

I can confirm that. Although I have gas and radiators in the old building, my heating runs 24/7 at the absolute lowest level. Here and there may still need some adjustment, but the comfort is indescribable. Never a: it is too warm, it is too cold, it takes too long to get warm. It is simply always 22 degrees.

To return once more to the original topic:

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

However, I also see other things coming your way:

[*]In summer, you will be roasted on the outside without shading or stewed on the inside. Or sitting inside with artificial light in the best sunshine
[*]You should think carefully about a terrace in the basement in front of the bedroom window. On one hand, the living area is on the ground floor, probably including the kitchen, dishes, etc., which would mean carrying things up and down in the house in order to enjoy the terrace. On the other hand, guests can constantly look into your bedroom or, apparently, this is 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 to the various challenges (at least for me and as long as I have not misunderstood your floor plan). The terrace will be built on stilts/pillars, about the height of the left annex, possibly with a staircase to the garden. Above it, there will be an awning or a roof. Such a construction, of course, “looking nice.”

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

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

To come back to the original topic:

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

We have the awning directly under the terrace roof (guided in rails)... there are no problems. Moisture doesn’t get in even when it rains, even if you leave it extended sometimes. Since the awning is integrated into the SmartHome, it retracts automatically in case of rain or strong wind anyway (even if it probably wouldn’t be necessary). Without a roof... good question, but sure, with rain and dirt it could quickly look "bad".

Do you have a photo of your sunshade handy? Aren’t there nowadays relatively weather-resistant awnings that can perhaps even withstand rain (nanotechnology or something)? Because I don’t find a permanently protruding roof, as you often see with urban villas, nice and it also takes away heat energy from you when heating the house!? As already wrote. It’s so often said for pure south orientation. But that’s the disadvantage. I know it from my parents who lower all the blinds on the south side in summer. On the one hand to keep the room temperature in check and also because of the plants on the windowsill. do you have a heat protection coating on your south-/west-facing windows? Can you recommend anything?

Do you have to assume that the floor-to-ceiling large windows are responsible for the heat?

Yes. Because the sun’s radiant heat goes through your windows - unless they have special glass.

What would you do, always lower all the blinds as soon as sun is forecast? That’s kind of annoying...

No, I wouldn’t lower the blinds at 24 degrees inside. has the simple solution: open the windows.

We have Fubkrollos via Somfy, would you buy the sensor that lowers the blinds directly at a certain temperature?

If anything, control it by sunlight in combination with room temperature.

Occasionally 24 degrees in the living room is still within my comfort zone; I wouldn’t invest in structural measures for that.

do you have a heat protection coating on your south/west-facing windows? Can you recommend something

No, it was just an idea in case other solutions don't work.