Not the Med, but we have a house in Portugal. Up to 10 or 15 years ago, airconditioning was not necessary: it was built with nice high ceilings, deep verandah, terracotta floors, external shutters etc. I can count on one hand the number of times the temperature got over 40C prior to 2016 and even in July and August the shade temperature rarely hit even 30C in Faro. It always cooled down enough on an evening that life was manageable and on particularly hot nights one would just have a dip in the pool before bed.
The truth is that the climate now is very different and has changed rapidly in the last ten years. The current heat dome in Portugal marks the second year in a row the temperature has risen above 35C in May, which genuinely used to be unthinkable. We regularly see 40C for two weeks in a row in July and August, it's much more humid, and it doesn't cool down at night. We put AC in three years ago.
Back in the UK, our new build's internal temperature can hit 30C even with windows closed and curtains pulled tight. Because of the plot layout we cannot plant anything to shade windows, and to fit external shutters would require replacing all of the outward-opening windows too. We'd happily do it, but it's a leasehold property and the freeholder won't let us. Being Manchester, if we leave windows open at night then nefarious dudes climb in through them and take things that belong to us, not them.
We've had a couple of portable AC units for a while, but bit the bullet last year and installed a complete system. It's an absolute game changer. As PPs have said, no would would seriously question heating a British home in winter to make it tolerable and healthy; why all the coy pussyfooting around about cooling it in the summer?