Can you imagine a hot summers day without indoor air-conditioning? Air-conditioning is used to create and maintain a certain temperature, relative humidity, and air purity conditions in indoor spaces. We feel its benefits in the shops, in our offices, and most importantly in the tranquility of or homes. One of the most refreshing feelings in the summer is entering into an air-conditioned space. Take a look below for 21 interesting and awesome facts about air conditioning.

1. In Ancient Egypt, water-soaked reeds were hung on window sills. The wind evaporated the water on the reeds and made the air around them cooler.

2. In Ancient Rome, water from aqueducts was circulated through the walls of certain houses to keep them cool.

3. Before air conditioners were developed to keep things nice and comfortable, people would use big blocks of ice to keep cool.

4. John Gorrie is considered the father of refrigeration and air conditioning. As a Floridian doctor in 1842, he developed a machine that made ice to cool the air for his patients. He was granted a patent to create a similar machine for homes and buildings but died before he could create it.

5. In 1899, a ventilation system was installed in the dissecting room at Cornell University—that way, the students could dissect cadavers without the smell.

6. When air conditioning technology became more prevalent in the early 1900s, movie theatre owners invested in AC systems to fill seats during the stickiest and hottest days of the year. Most people didn’t have home air conditioning, so the movie theatre was the perfect escape. “Refrigerated Air” was often highlighted in theatre advertisements.

7. In 1902, Willis Carrier, who worked for a publishing company, decided enough was enough with his paper expanding and ink running during the summertime. He came up with the ideas for the first widely known factory-scale cooler!

8. Some of the first air conditioners were used for publishing companies because, without the cool air, the paper in the office would expand and contract throughout the year.

9. The New York Stock Exchange Building in NYC was one of the first buildings to use air conditioning in 1903.

10. The term “air-conditioning’ was coined in 1906 by a North Carolina textile manufacturer after air-cooling technology improved the quality of the fabric being produced in the plant.

11. The first fully air-conditioned home was built in a mansion in Minneapolis in 1913 by Charles Gates. Sadly, he died before he could ever experience it.

12. Herbert Hoover was the first American president to have the luxury of AC. He spent $30,000 on the system not too long after the stock market crash in 1929.

13. In 1931, air-conditioning was nowhere near wide-spread and only the wealthiest people could afford it for individual rooms. Invented by H.H. Schultz and J.Q. Sherman, these units sat on a window ledge and cost between $10,000 and $50,000. That’s the equivalent of $120,000 and $600,000 today!

14. In 1939, the American luxury car company Packard invented the first automobile with air-conditioning. To activate the air-conditioning, the driver had to stop the engine, open the hood, and disconnect a compressor belt. It wasn’t the most consumer-friendly design, but it worked.

15. Air conditioning became something of a status symbol after World War II. Over one million window units were sold in 1953.

16. Air conditioning helped grow populations in states like Texas, Florida, Arizona, and Nevada in the 1960s.

17. We wouldn’t have medications that fight everything from the common cold to cancer treatments if it weren’t for our cooling systems. Although we like to think that the purpose of air-conditioning is comfort, AC has other uses as well. Researchers that study pharmaceuticals require the air in the laboratory to be cooler and less humid. Also, air-conditioning in hospitals helps keep the production of bacteria down and helps prevent the spread of disease.

18. Before air conditioners, it was way too hot to learn during the summer months, so summer vacation was born. Fortunately, the idea stuck, and kids today get to enjoy the summertime with the benefit of a cooling system.

19. Scientific studies have shown that the introduction of air conditioning has lowered the natural human tolerance for heat.

20. Air conditioners have proven to have a positive effect on people who suffer from asthma. They’re able to remove allergens and other smaller particles from indoor air which means less sneezing and more relaxing.

21. South Korea is now the largest producer of air conditioning in the world.