Lee Kuan Yew, the iron-willed founder of modern Singapore, was once asked what the most important invention of the 20th century was. He didn’t say penicillin, which has saved over 500 million lives, or the nuclear bomb, which has shaped geopolitics like nothing before. He didn’t even say TV!

Instead, Lee had a simple two-word answer: “Air conditioning.” Without air conditioning, Singapore, where temperatures regularly reach into the 90s with tropical humidity levels, would never have developed from a tiny city-state with a per-capita GDP that was a third of Western Europe’s in 1960 to one of the most prosperous countries in the world.

Air conditioning is as essential to the modern world as the internet itself. But like the internet, A/C gets a bad rap. Cooling already eats up 10 percent of global electricity, and demand from air conditioners is expected to triple by 2050 without tougher energy efficiency standards. Many units still use refrigerant gases that produce a planetary warming effect that is thousands of times that of a similar amount of CO2.

Air conditioning is also a physical manifestation of the energy gap between the rich who can afford it, and the poor who must sweat. It has enabled the development of

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