Floor plan for 11m x 8.25m, ok?

Are 1.51m windows actually the standard size for windows?

No, that is not "the standard size," but it is a common measurement. Between 1.51 m and 1.76 m there is also 1.635 m (and then further 1.885 m and 2.01 m). It makes sense both aesthetically and economically not to use thirteen different formats for eighteen windows. Therefore, my praise on this point. Firstly, a reasonable "variety" of formats was chosen overall, and secondly, not seven different ones on the same facade.

No, that is not "the standard size," but it is a common dimension. Between 1.51 m and 1.76 m, there is also 1.635 m (and then further 1.885 m and 2.01 m). It makes sense both aesthetically and economically not to use thirteen different formats for eighteen windows. Therefore, my praise on this point. Firstly, a reasonable "variety" of formats was chosen overall, and secondly, not seven different types on the same facade.

We also find it basically successful. The architect said that according to the light calculation formula, there is more than enough window area. If a 1.76 m window would cost me 200€ more than a 1.51 m one, that would be times 5 not the end of the world. Although it does not necessarily have to be.

If a 1.76m window compared to 1.51m would cost 200€ more, that would be five times, not the end of the world. Although it doesn't necessarily have to be that way.

I may not have expressed myself clearly enough:

Would 1.76m wide windows at the top maybe be a solution?

No, as it is, it is perfectly balanced. I wouldn't change a thing about it.

If possible, I would swap the guest bathroom with the [absteller], so you don't always have to go through the [Windfang] when going to the toilet from the living room. Unless the [absteller] is also supposed to function as a pantry.

I would swap the guest bathroom with the storage room if possible, so that when going to the toilet you don't always have to go through the entrance area from the living room. Unless the storage room is also supposed to function as a pantry

What speaks for a swap for me: as soon as you make louder noises on the toilet, everyone in the living room hears it. oops:

The architect also said that about the noises. But yes, the storage room is the pantry

@all glad that the floor plan has no major "defects" so far. The structural stability is also fine, according to the architect, hence the small L around the chimney.