99% Invisible

When air conditioning was invented in 1902, it was designed to take out the humidity in the air so printers could run four color magazines, without the colors becoming offset due to the paper warping from moisture. A young engineer named Willis Carrier developed a system that pumps air over metal coils cooled with ammonia to pull moisture from the air, but it had a side effect -- it also made the air cooler. Very quickly Carrier began to think about how it could be used beyond printing. Ultimately, air conditioning would dramatically change where people in the United States lived and the design of homes and other buildings. Thermal Delight Subscribe to SiriusXM Podcasts+ on Apple Podcasts to listen to ad-free new episodes and get exclusive access to bonus content.