Window purchase - Which windows and from which manufacturer?

In the case of an extension, there will probably be some windows that need to be adjusted in size to match those of the floor below. Otherwise, one can save by using "standard stock sizes" (for the windows) and not too colorful a variety of formats (for the surroundings such as lintels, etc.). Extension also means an upper floor, so there is less burglar protection effort than on the ground floor (except over garages/canopies, etc.).

Without knowing the project further, one can say little "concrete" about it. For example, we do not know what the rest of the house (existing building) looks like, i.e. what materials fit with it.

Great, thanks guys!
It already helped me a lot!

Unfortunately, these are all companies from Germany, Karsten... But from what I have seen, Drutex actually has a distribution in Austria, so I will inquire there as well. Thanks for the tips!

Best regards

So we got Internorm windows.
Great quality and probably from Austria.
Unfortunately, they were only installed recently, so no long-term statement yet.

In terms of price, we had alternatives from Unilux, but they were somewhat more expensive with "worse" features.
We decided on aluminum cladding and fully concealed fittings (because of cleaning - WAF )

Regards