Dear Europeans:
Yes, we understand that central air is hard to build into old homes. Yes, we also understand that your windows are a bit different.
But here's the part that confuses us.
Why do you have to buy window A/C designed for American windows?
Why can't Europeans, living in Europe, design A/C units to fit European windows, for other Europeans, who live in Europe?
Yes, Willis Haviland Carrier was an American, but he solved this problem in 1902. You have had over one hundred years to adapt his work to a slightly different aperture.
Do you not build things anymore? Are there some regulations preventing you? Will your neighbors just relentlessly shame you for having air conditioning?
Seriously, unsarcastically, what the hell is the obstacle, here?
"Who told the idiot Americans we can't open our windows?"
You did.
You said your windows don't open to accommodate ac units. Others posted actual regs saying they can't fully open, or bars have to be installed, reno projects are hard to get approved, etc.