Air conditioning changed everything: https://www.energy.gov/articles/history-air-conditioning https://www.energy.gov/articles/history-air-conditioning > Engine

Air conditioning changed everything: https://www.energy.gov/articles/history-air-conditioning https://www.energy.gov/articles/history-air-conditioning > Engineer Henry Galson went on to develop a more compact, inexpensive version of the window air conditioner and set up production lines for several manufacturers. By 1947, 43,000 of these systems were sold -- and, for the first time, homeowners could enjoy air conditioning without having to make expensive upgrades. > By the late 1960s, most new homes had central air conditioning, and window air conditioners were more affordable than ever, fueling population growth in hot-weather states like Arizona and Florida. Air conditioning is now in nearly 100 million American homes, representing 87 percent of all households, according to the Energy Information Administration.