Overall, you'd have to say that air-conditioning has been a boon. For instance, the computer revolution almost certainly would not have happened without it : Those first big main frames needed massive A/C and even the desktops and laptops that followed still don't like heat. And it allowed the rise of the South to economic power by cooling its factories and offices enough to permit Teutonic levels of efficiency through the year. Some might not be all that happy with that rise, especially with its political effects. My Southern relatives, however, were happy that an extra couple of months of comfort and productivity had been added to their year. Still, A/C's absence did have some benefits. One was that the summer heat slowed you down and made you look at the world through a somewhat different optic, giving you a more rounded sense of life and the passage of the seasons. It spawned a certain kind of imaginative rumination. Another benefit was that the enforced slowness encouraged a leisurely friendliness, a back-porch socializing.
A heat wave made cold drinks more refreshing, swimming more refreshing and the cool break of a thunderstorm more exhilarating.
Except in urban slums, there were usually ways to avoid the worst of the heat. In my family, my brother and I, who lived on the very hot third floor, would move downstairs, to the first floor, or even the cellar, with sleeping bags, where it rarely got above 65. There we'd be lulled to sleep by the drug-drip-drip of the dehumidifier. Or we and our other siblings would sleep in the backyard, although that tended to get very uncomfortable soon -- first you'd be sweaty hot and then chilled before dawn. Meanwhile, fireflies produced brief amusement.
Few people had car air-conditioning until the '70s. You'd drive with the windows down, which, besides the cooling from the wind, had the benefit of blowing away the cigarette smoke.
New Englanders used to say that they didn't need A/C because it didn't stay hot enough long enough. (Such assertions are part of New Englanders' claims to be particularly tough and resilient when compared to people from other parts of the country. )
But when it is hot in New England it's hotter than most of Florida. The great New England heat wave of early August 1975 had temperatures up to 113. My wife and I were driving back to steamy Philadelphia from seeing friends in New Castle, N.H., at the time. The sides of the roads were lined with dead cars with steaming radiators. Luckily for us, we were in a VW bug -- air-cooled (though it was to believe that the air that day could cool anything). Like flat tires, steaming radiators are rare now. Tires and cars are better.
When we got back to Center City Philly we found a note in the apartment from someone who a few days before had been camping out there while we were away. It relayed a message from one of my sisters that my father had had a heart attack driving to work in Boston. (I know the car wasn't air-conditioned. ) He had the presence of mind to drive to the hospital, but died a couple of days after his arrival; at a rather young age, I had become the family patriarch.
I never heard again from the person camping out in our apartment; he was probably too mortified by the circumstances to contact us. But hello, John Whitfield (a former Wall Street Journal colleague who had decided to go to the University of Pennsylvania Law School) --- wherever you are on the road to Social Security.
I hope that central air conditioning is giving you a long, long life.