summer thermal protection - reduction of windows?

A room with 18 sqm west-facing windows should easily be practically uninhabitable for half the year.

I can't shake the feeling that the draftsman used magic ink. I don't see any drawing here at all, but comments as if there had once been drawings. I've only encountered this phenomenon in this form with the Greens so far.

During the planning (architect for designs, draftsman, structural engineer) it was said: no problem at all. It is clear that we now have to do something. But 6 roller shutters or venetian blinds really hit hard. Therefore, we are looking for another option for the proof.

Nowadays, these sliding shutters / hinged shutters / folding shutters made of wooden slats are installed more often on the outside. That can look quite good, whether it is cheaper than a venetian blind I don't know. We have venetian blinds everywhere and that is a clear difference to roller blinds in the old house when the sun really beats down. A very cheap option might be vertical awnings without side guide, but that doesn't look trustworthy to me. Maybe a well-placed sun sail outside will help you too, especially if you are building into the hillside. But honestly: I wouldn't save on shading in a new build but rather make compromises elsewhere. If you build such a half-hearted cheap solution now, you will invest a lot of money in correcting it in a few years with the increasing climate change. That is my expectation regarding this.

What is the surcharge that your [GU] demands? Are you building at all with [GU]?

Due to the offset in the terrain, our living/dining room and the adjoining semi-open kitchen are located lower. Ceiling height approx. 3.8m. Windows to the garden: two 3x3m to the west, and a large corner window to the east.

Window/room ratio approx. 40%.

I can't imagine that.

Current proposal: No windows, only a glass door with a transom. Ergo: we can no longer look into our garden.

And that is the alternative to 40% window area?
Either 3 x 3 or a transom above a glass door?
And you can't look through a glass door?
Apparently, it's either 100% or 15%!
What about 50 or 60% of your 3 x 3?
For example, 2 x 3?

That is not possible cost-wise.

That, however, also makes me smile. You know that one should plan a 10% buffer of the house price for unforeseen expenses?

A more cost-effective (in the long run!) alternative to external shading (Raffstore, roller shutter, blinds,...) you will not find in my opinion. And as has been written here several times, it simply makes sense to install them. So the only alternative probably remains to refinance or have smaller windows (although personally I would also equip smaller windows with shading)

To assess, the floor plan and the elevations would need to be seen…