@gwynnion At least where I live, modern housing is *worse* in the summer heat than old housing was - because it's been designed specifically to keep heat *in*. A large amount of insulation material in the walls, triple-paned windows, seals that strongly reduce cross-ventilation, large south- or west-facing windows.
This is because aside from the newly terrible summers, we also have terrible winters, and this design helps keep a home warm with less artificial heating (which, as a footnote, AFAIK is *more* energy-intensive than cooling in the summer). It takes a lot more energy to cool down a modern Scandinavian house than most American ones, because the entire passive design is basically fighting against it. The flip side of this is very evident in the winters, where modern houses are a lot cheaper to keep warm.
The electric grid here is strained already (though fortunately the new government has forced data centre buildout to the back of the queue for new on-grid projects). More capacity is being built - but that takes time, especially when simultaneously phasing out coal and gas.
I can't personally run balcony solar because I don't have a balcony. Furthermore, I live in an inner city area where rooftop solar is prohibited due to cultural-heritage preservation law (*lots* of old, historical architecture) - and externally visible AC likewise. Though I expect that most of the cultural heritage preservation laws are going to be abolished soon because those were a luxury of less-terrible times.
(Should we tear down all our housing and rebuild for terrible summers? Perhaps, but our terrible winters are *even longer* than the terrible summers, and when the AMOC collapses we'll be getting a new ice age here. I expect that within my lifetime I'll be living in a strictly rationed "war economy" type arrangement, except not due to war but climate devastation.)