The history
4,500 years from wet clay jars and Persian ice houses to the billions of air conditioners humming in a warming world.
People have always fought the heat with water, wind and shade. Then scientists found that a liquid soaks up heat as it boils away, and engineers learned to squeeze that vapour back into a liquid and do it again, over and over. In 1902 a young engineer used the idea to control the air in a printing plant, and cooling spread to cinemas, homes, cars and whole cities. The chemicals that made it safe then tore a hole in the ozone layer, and the world had to fix them, while more and more people need cool air to stay healthy.
c. 400 BCE
Ice houses for summer ice
Persian yakhchāls, Iran
1756
Public demonstration of artificial cooling
William Cullen, Scotland
1834
Vapour-compression refrigeration machine
Jacob Perkins, England
1902
Modern air conditioning system
Willis Carrier, USA
1906
The words “air conditioning”
Stuart Cramer, USA
1939
Car with air conditioning from the factory
Packard, USA
1961
Split air conditioner
Toshiba, Japan
1980
Inverter home air conditioner
Toshiba, Japan
2500 BCE – 1800
No machines that make cold. People cool water in porous jars, store winter ice, catch the breeze with towers and pull on fans by hand.
2500 BCE
c. 2500 BCE
There is evidence that evaporative cooling was used in Egypt as early as the Old Kingdom. Paintings show servants fanning water jars made of porous clay. Water seeps through the clay and evaporates from the outside, which chills what is left inside.
Why it mattered. It is the same trick every air conditioner uses: a liquid that evaporates carries heat away with it.
400 BCE
c. 400 BCE
Records suggest that Persians were building yakhchāls, domed ice houses with deep pits and thick walls, by about 400 BCE. They stored winter ice through the scorching summer. Houses in the region also used windcatchers, tall towers that pull breezes down into the rooms; Egypt, Iran and the UAE all claim to have invented them.
Why it mattered. Long before machines, people learned to keep cold and move air with nothing but clever building.
180
c. 180 CE (dates vary)
Chinese records credit the Han dynasty craftsman Ding Huan with a rotary fan of seven wheels, each about 3 m across, turned by hand to cool a hall. Sources disagree on when he lived. Centuries later, in 747, a Tang emperor's Cool Hall is said to have used water-powered fan wheels and fountains.
Why it mattered. Moving air across skin helps sweat evaporate, the oldest way to feel cooler.
1780
1700s–1800s
In India the pankha began as a hand-held fan of palm leaf or woven bamboo. In colonial times the word came to mean a big cloth fan hung from the ceiling and swung by a servant, the punkah-wallah, who pulled a rope for hours. Several could be tied together to cool a whole courtroom or office.
Why it mattered. It was air conditioning by muscle, and it shows how much work people would do to move air.
1750 – 1900
Scientists find that evaporating liquids steal heat. Ice is shipped around the world, and the first machines squeeze a vapour back into a liquid to make cold on demand.
1756
Cullen, a doctor and chemist, used an air pump to lower the pressure over a container of ether. The ether boiled at room temperature and pulled so much heat from its surroundings that it made a little ice. It was the first documented public demonstration of artificial refrigeration.
Why it mattered. It showed that lowering the pressure lets a liquid boil cold and soak up heat, the heart of the refrigeration cycle.
1758
Franklin and the chemist John Hadley kept wetting a thermometer bulb with ether and blowing on it with bellows. The reading fell from about 18 °C to about −14 °C, and a skin of ice grew on the bulb. Franklin wrote that you might freeze a man to death on a warm summer's day this way.
Why it mattered. A dramatic proof that evaporation can pull things far below freezing.
1806
Tudor shipped ice cut from New England ponds to Martinique in the Caribbean, and people laughed at the idea. By 1833 a ship packed with 180 tons of ice sailed to Calcutta, and the trade went on to reach Madras, Bombay, Hong Kong and more.
Why it mattered. Cold became something you could buy, and the world grew hungry for a way to make it anywhere.
1823
Faraday put gases such as chlorine under high pressure until they turned into liquids, and went on to liquefy several more, including ammonia. When the pressure was released, the liquid boiled back into a gas and grew cold.
Why it mattered. Squeeze to make a liquid, release to make cold: that is what an air conditioner's compressor and valve still do.
1834
Perkins, an American inventor living in London, patented a closed machine that evaporated a liquid to make cold, then pumped the vapour back into a liquid to use again with no waste. His prototype worked, but it never sold.
Why it mattered. Evaporate, compress, condense, repeat: this closed loop is the cycle inside almost every fridge and air conditioner today.
1851
6 May 1851
Gorrie cooled the rooms of patients sick with fevers like yellow fever by blowing air over ice. Shipped ice was scarce, so he built a machine that compressed air to make ice, and won US patent 8,080. It failed as a business, but his model is kept at the Smithsonian.
Why it mattered. It was one of the first attempts to cool rooms, not just food, with a machine.
1882
Wheeler put a two-bladed propeller on an electric motor and made a desk fan. The same year Diehl adapted the motor from a Singer sewing machine to drive a fan on the ceiling.
Why it mattered. Electric fans brought cheap moving air into homes, and every air conditioner still has fans inside.
1900 – 1945
Air conditioning is born in factories to control humidity, then moves into cinemas, offices and the first room units, cooled by new ‘safe’ refrigerants.
1902
17 July 1902
A Brooklyn printing company had a problem: in humid summers the paper swelled and the colours printed out of line. Carrier, a 25-year-old engineer, designed a system that blew air over cold coils, which cooled the air and made its water vapour condense out. It controlled temperature and humidity together.
Why it mattered. It is widely regarded as the first modern air conditioning system, and it was built to dry the air, not to cool people.
1906
In a May 1906 speech to cotton mill owners, the engineer Stuart Cramer used the words ‘air conditioning’ for controlling the moisture and cleanliness of air in mills. That January, Carrier had been granted US patent 808,897 for an ‘Apparatus for Treating Air’.
Why it mattered. The idea got its name, and Carrier's company later took the name too.
1911
3 December 1911
Carrier presented his ‘Rational Psychrometric Formulae’, which link temperature, humidity and dew point. Engineers could now calculate how much cooling and drying a building needed, instead of guessing.
Why it mattered. It turned air conditioning from trial and error into engineering.
1922
Carrier unveiled the centrifugal chiller, which uses a fast-spinning wheel to compress refrigerant vapour. It was smaller, safer and more reliable than earlier machines for cooling big spaces.
Why it mattered. It made it practical to cool theatres, shops and offices full of people.
1925
Memorial Day, 1925
Carrier's system opened at the Rivoli on Broadway. The film studio boss Adolph Zukor watched the fanning crowd grow calm and reportedly said: “Yes, the people are going to like it.” Within about five years Carrier had cooled more than 300 cinemas.
Why it mattered. Cinemas became summer escapes, and the summer blockbuster was born.
1930
1928–1930
Early refrigerants like ammonia and sulfur dioxide were toxic, and leaks killed people. A General Motors team made dichlorodifluoromethane, the first CFC, sold as Freon. In 1930 Midgley breathed some in and blew out a candle to show it was neither poisonous nor flammable.
Why it mattered. Safe refrigerants let air conditioners into homes and cars, but no one yet knew what they would do to the sky.
1932
1931–1932
Schultz and Sherman designed a unit that sat on a window ledge. It went on sale in 1932 for $10,000 to $50,000, far more than a house, so almost no one bought one.
Why it mattered. The shape was right, and the window unit became the most common room air conditioner.
1945 – 1990
Window units become affordable, Japan invents the split system and the inverter, and hot places fill with people and buildings.
1947
1945–1950s
After the Second World War, cheaper and smaller window units arrived, and more than 43,000 were sold by 1947. Air conditioning helped people and factories move to the hot, sunny American South and West, the Sun Belt.
Why it mattered. Cooling changed where people could comfortably live and work.
1961
Toshiba, which had made what it calls Japan's first 1-horsepower window air conditioner in 1953, released what it calls the world's first split air conditioners. The noisy compressor sits outside, and a slim unit on the wall inside blows the cool air, joined by thin copper pipes.
Why it mattered. The split system became the most common air conditioner on Earth.
1980
Toshiba released what it calls the world's first inverter-based home air conditioner; other sources say inverter models reached shops in 1980–1981. Electronics change the compressor's speed smoothly instead of just switching it on and off.
Why it mattered. Running slowly and steadily saves a lot of energy, and most new air conditioners now work this way.
By the numbers
In the United States, air conditioning went from a luxury to nearly every home.
1974 – 2016
Scientists discover that refrigerant gases destroy the ozone layer and warm the planet. The world agrees, step by step, to replace them.
1974
28 June 1974
Molina, a young Mexican chemist, and Rowland worked out that CFCs drift up to the stratosphere, where sunlight breaks them apart. The chlorine they release destroys ozone, the gas that shields life from ultraviolet light. They shared the 1995 Nobel Prize in Chemistry with Paul Crutzen.
Why it mattered. It revealed that the gases in fridges and air conditioners could harm the whole planet.
1985
16 May 1985
Measurements from Antarctica showed that ozone over the South Pole was dropping sharply every spring. The scientists linked the losses to chlorine from CFCs. The next year Susan Solomon led an expedition that helped explain how icy polar clouds speed up the damage.
Why it mattered. Seeing a real hole made the danger impossible to ignore.
1987
16 September 1987
Countries agreed to phase out the chemicals that destroy ozone, starting with CFCs. It became the first treaty ratified by every UN member state. Air conditioners switched from CFCs to HCFCs like R-22, and later to gases with no chlorine at all.
Why it mattered. It is widely seen as the most successful environmental treaty ever, and the ozone layer is slowly healing.
2012
November 2012
In 1996 Carrier sold the first home air conditioner using R-410A, a gas that does not harm ozone but traps a lot of heat. In 2012 Daikin launched air conditioners in Japan using R-32, which Daikin says warms the planet about a third as much as R-410A and needs less gas.
Why it mattered. Each switch kept the same cycle but made the refrigerant kinder to the sky.
2010 – today
Heat waves grow, billions of people want cooling, and the race is on to make air conditioners far more efficient.
2018
14 May 2018
The IEA counted about 1.6 billion air conditioners in use and warned that the number could reach 5.6 billion by 2050. Most people buy units less than half as efficient as the best ones for sale.
Why it mattered. It made cooling efficiency one of the biggest energy questions of the century.
2025
About 3.5 billion people live in regions with high temperatures, but only about 15% of them own an air conditioner, says the IEA. As heat waves grow, demand is soaring in India, Southeast Asia and Africa.
Why it mattered. Cooling is becoming a matter of health, and making it efficient will shape the climate.
By the numbers
IEA estimates of the global stock of air conditioners, then its 2018 projection: the number could more than triple between 2016 and 2050.
Did you know?
The first modern air conditioner was built to stop paper swelling in a print shop, not to make people comfortable.
In 1930 Thomas Midgley breathed in Freon and blew out a candle with it, to prove the new refrigerant was safe.
The Mughal emperor Akbar had ice carried from Kashmir to Delhi, Agra and Lahore by relay.
Within about five years of the Rivoli opening in 1925, Carrier had cooled more than 300 cinemas.
In 2016, only 8% of the 2.8 billion people living in the hottest parts of the world had an air conditioner, compared with about 90% of homes in the United States and Japan.
The people
1783 – 1864 · Merchant · USA
The ‘Ice King’ who shipped New England ice to the Caribbean and India.
1791 – 1867 · Chemist and physicist · England
Liquefied gases under pressure and saw them cool as they boiled back.
1766 – 1849 · Inventor · USA and England
Patented the first vapour-compression refrigeration machine.
1803 – 1855 · Physician · Nevis and USA
Built an ice machine to cool fever patients in Florida.
1876 – 1950 · Engineer · USA
Built the first modern air conditioning system and the science behind it.
1868 – 1940 · Textile mill engineer · USA
Coined the term ‘air conditioning’ in 1906.
1892 – 1971 · Mechanical engineer · USA
Early woman engineer at Carrier who worked on measuring humidity and human comfort.
1889 – 1944 · Chemist and engineer · USA
Helped create Freon, the CFC refrigerant later found to destroy ozone.
1943 – 2020 · Chemist · Mexico
Showed that CFCs destroy ozone; first Mexican-born Nobel laureate in chemistry.
1927 – 2012 · Chemist · USA
Molina's partner in the 1974 ozone warning; shared the 1995 Nobel Prize.
1930 – 2013 · Geophysicist · England
Led the British Antarctic Survey team that reported the ozone hole.
born 1956 · Atmospheric chemist · USA
Explained how icy polar clouds help chlorine destroy ozone over Antarctica.
Where it happened
Sources
Dates marked “c.” are approximate, and historians sometimes disagree about who was first. If you spot a mistake, tell us.
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