Until a couple of years ago it was IMO not necessary, especially for modern buildings with good isolation. Hot summer was maybe 2-3 weeks. But now I wouldn't sa

Until a couple of years ago it was IMO not necessary, especially for modern buildings with good isolation. Hot summer was maybe 2-3 weeks. But now I wouldn't say that anymore, but Paris agreement / trying to protect the climate as hard as possible is still more important than this. I do think however that we need to take measures to protect the oldest and youngest inhabitants.