> you just need to let people use AC properly (..) every person in southern Europe should have an AC unit in their bedroom and deaths will go down substantially.

Yes, exactly: install AC where it truly helps and where it is truly needed. That's the point I was trying to make. Most of the rest is solved far more efficient by things like installing shades. In other words: don't go all-out on giant whole-home AC without first stopping the huge inflow of new heat.

> if Europe stopped being so averse to new construction

We're not, there's plenty of new construction over in Europe.

The difference is that European buildings are built to last, so structurally there's no need to tear them down after a couple of decades. They are perfectly usable for another half-century after a minor renovation (including retrofitting AC!), so why destroy a charming historic district for absolutely no reason?

That doesn't mean buildings are never torn down, of course. Right now a lot of post-WWII rental units are being replaced by new construction, as they are architecturally nothing special and renovating them to modern standards is simply way more expensive than replacing them entirely.