Yes we can all say GOD BLESS YOU to Willis Carrier who was inventor of modern air conditioning July 17, 1902 !!! Then in 1931 H.H.Schultz &J.Q.Sherman invented an individual room AC that sits on a window ledge. The units became available for purchase a year later & are only enjoyed by the people least likely to work up a sweat- the wealthy .It cost between $10,000 & $50,000. That's equivalent to $120,000 to $600,000 today
Then post WW2 economic boom the AC becomes just another way to keep up with the Joneses . More than 1 million units are sold in 1953 alone Central Air was 1970's .