@doonxib @sickburnbro Not really. My grade school was built, brand new, without air conditioning. Didn't get AC installed until about 4 years later, and this was in the deep South.

Out West, AC in homes didn't break the 50% mark until the 2000s according to the gubmint.

Natural ventilation starting getting it in the shorts in the 60s-70s with the rise of the Shitty Architecture movement that said everything must be grim and concrete, but AC got a helluva lot better in the 80s-90s which made it more practical to install everywhere, and standard building practices started leaving above ceiling space in commercial construction.