E.g. you can buy a heatpump but you can't drill the hole in the outer wall.
In germany and austria most if not all windows also either open fully to one side or basically bend inwards so you can't install the ac units you install directly into the windows[1].
[1]https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2F...
edit: qualified the law statement