At the turn of the 20th century, engineers referred to early air cooling technology as “man-made weather,” a splendidly optimistic phrase suggesting that science was about to master those most unconquerable of all natural forces—the elements. In the decades that followed, “air conditioning” became the preferred term—a more pragmatic description of filtering, cooling and optimizing the moisture of interior air.

This less impressive label hardly diminishes the huge impact AC has had on the planet. The technology has made much of the world comfortably habitable for billions of people and facilitated the explosion of new cities. As historian Hal Rothman explains in Neon Metropolis, “air-conditioning was the catalyst for habitability” in the American South. Every visitor to L...