Europe is pretty big and varied.

>The problem in Europe isn't keeping warm in the winter but keeping cool in the summer. In part thanks to their near-total lack of AC in residential buildings,

The times they are a-changing. Every house on my 21 year old estate came with ac. I'd assume the same for newer constructions. People rarely use it due to the price of electricity. Temps get well over 30C for a couple of weeks in august.