Solarpunk technology

In southern Europe AC is common. In northern Europe floor heating with a central heatpump system seems to be the most common solution for new builds (in the part of Europe I know at least), but it was unfortunately seldom installed with cooling ability. New builds in northern Europe are very well insulated, and double glazed glass with a low solar transmission factor is common, as are built-in blinds. Proper ventilation was an issue when we first started with insulating and sealing everything up, the rules have since been made more humane, but imo still too focused on mechanical solutions.

Every new build/renovation has to have an energy + ventilation study done and meet certain minimum standards. The result of that study is prominently featured on any immo platform, so renters know what to expect.

But when it's 35+ °C outside for several days in a row, those new builds without active cooling still get too hot. Our legislation simply hasn't caught up yet. When it gets that hot, people now often make due with mobile airco units to keep a few rooms livable, which is silly for a home that's only a few years old imo. We should have been prepared for this, we knew it was coming :)