When the King and Queen of Britain stayed in Washington in June 1939, with the temperature in the sticky 90s F (high 30s C), they asked for hot-water bottles at the White House! Presumably, they were trying to make some point about British grit…
For the rest of the US, air conditioning is a necessity. Not only is it essential, but it’s changed the economic and political way of life of the country. For example; the relocation of businesses in the south wouldn’t have happened without it. 
Would Atlanta or Houston or Miami have been able to hold their own against New York – where Summer is unpleasant but just about bearable – without air conditioning? And would car-makers see Alabama as viable without it?
There’s also a reputable argument that air conditioning service, by making the South economically viable, kept the South alive politically too. One of the people who might thank air conditioning, accordingly, is former President George W Bush. And Democrats only seem to win when they have a strong Southern association – like a certain Bill Clinton from Arkansas.
Half a century ago, less than a third of Americans lived in the South; now it’s more than half…