It’s not banned, but getting permission to install the outside unit is essentially “hard” in some parts of Europe. In England, if you own a house, you generall

It’s not banned, but getting permission to install the outside unit is essentially “hard” in some parts of Europe. In England, if you own a house, you generally have permitted development rights to install one, subject to some fairly common-sense rules. If you live in a flat, though, it’s a very different story: you will need planning permission *as well as* freeholder consent, and the process generally involves engineering/structural/architect drawings and freehold-consent paperwork. The freeholder can also charge you their legal and administration costs, even if they ultimately reject the application. Essentially it's >5K of paperwork which might be wasted if it's rejected even just to install a single 5KW split. So in the hottest parts of London and other major cities, where a large proportion of people live in flats, installing AC can be very difficult in practice. In the cooler commuter towns, where houses are much more common, it’s considerably easier. Why can't they build it into new flat blocks/houses? Nothing outright prevents it but everyone does their best to discourage it. The London Plan, for example, uses a “cooling hierarchy” which 'seeks to reduce any potential overheating and also the need to cool a building through active cooling measures' so good luck getting planning for it.