> Several countries require AC installation to be approved by the equivalent of a homeowners association or impose noise ordinances that increase compliance costs and paperwork. This is not unique to ACs. Anything on the outside of a building requires your co-owners to agree.
> co-owners HOAs don't make neighbors co-owners of your own property, do they? Anyway HOA is something that shouldn't even exist. Or at least not with power to prevent people from having air conditioning in their home.
Home-owner associations in Europe are frequently set up for apartment buildings, in which case, yes, the roof, foundation, hallways, stairwells, main piping, electricity, etc are all legally co-owned. Primary purpose of HOAs is to save for & plan long-term maintenance on the entire building.
HOAs for neighbourhoods, or blocks with single-family homes or terraced houses are pretty rare in Europe.