With much of the nation baking under intense heat, look back at the history of fans, air conditioners and other ways humans have tried to stay cool through the centuries.
If you had enough money in ancient Rome, you could cool your home with water pumped from aqueducts into pipes circulating through the walls of your home, according to history.com.
Evaporative cooling, which adds moisture to the air that cools things down as it evaporates, dates back to ancient Egypt. Egyptians would hang wet mats in doorways or have slaves fan jars full of water. Similar techniques can be found in American Indian communities, the American West and 19th-century textile mills.
Medieval Persians used wind towers, which worked kind of like a reverse chimney. Tall windows captured wind, which was funneled into and circulated around homes, according to history.com.
Nineteenth century American settlers often built sod homes, which often weren’t permanent but did keep cool in the summer, according to history.com.
Oscillating fans began showing up in the U.S. in the early 20th century, thanks to electricity and inventor Nikola Tesla’s alternating current motors, according to Slate.
Willis Carrier built the first modern air conditioner in 1902 to keep humidity down (and keep pages from wrinkling) in the New York printing plant where he worked, according to articles in Slate and The Atlantic. It accomplished its goal by sending air through coils cooled by water.
Window air conditioning units were introduced in the 1930s, but were still too expensive for most Americans, according to Time.
In the 1940s and 50s, air conditioners were marketed to offices as a way to increase productivity. The industry had stats to back this up, including one study that showed typists in a cooler office increased output by 24 percent, according to Time.
The world’s first air-conditioned bus was equipped in San Antonio, Texas, in 1946, according to the Carrier Corporation. Air conditioning in cars began to become a status symbol in the mid-1950s, according to the Atlantic.
The Packard Motor Car Company first offered air conditioning in cars in 1939, but it was discontinued two years later. The Chrysler Imperial was the first car after that to feature a cooling system in 1953.
More homes got air conditioning in the 1950s, but it would still be a little while before the trend really took off. Ten percent of homes had air conditioning in 1965, but that number jumped to 86 percent by 2007, according to Slate.