Korea's record 42.5 C heat wave revives the legacy of the 'father of air conditioning'

Every summer, as heat waves return, a black-and-white portrait of an American engineer circulates online. It is Willis Haviland Carrier (1876–1950), the father of air conditioning. At the peak of each heat wave, internet users attach the same joke to his image: he deserved a Nobel Prize. A somewhat exaggerated claim follows — that he expanded the portion of Earth's surface where humans can live. This year, the joke feels less like a joke.

The mercury in Yangsan, South Gyeongsang Province, climbed to 42.5 degrees Celsius on Sunday — the first time South Korea's temperature has exceeded 42 C since modern meteorological records began in 1904, a span of 122 years. Yangsan had already set consecutive national high-temperature records of 41.4 C on July 31 and 41.6 C on Aug. 1, making it three days in a row. The previous record was 41.0 C, set in Hongcheon in 2018. The Korea Disease Control and Prevention Agency reported 1,889 cumulative heat illness cases and an estimated 14 deaths around that period, while livestock deaths reached 432,450.

The extreme heat was not confined to South Korea. Death Valley in California recorded a high of about 51.1 C in July. Europe saw a string of all-time national records — 45.1 C in Spain, 44.3 C in France and 41.3 C in Germany. The World Health Organization said more than 1,300 people died from heat across Europe in late June, with an estimated 1,000 of those deaths occurring in France.

Air conditioning has been singled out as a key factor behind Europe's disproportionate toll. According to the International Energy Agency, household air conditioning penetration in Europe stood at roughly 20 percent in 2019 and is estimated at around 25 percent in 2026. In France, 25 percent of homes have some form of cooling equipment, but only 7 percent have a dedicated air conditioner, excluding fans. The primary reason is that the North Atlantic Current and prevailing westerly winds historically kept European summers mild, suppressing demand from the outset.

Other barriers compounded the problem. Historic stone buildings thick enough to qualify as cultural heritage are difficult to retrofit with air conditioning units. Industrial electricity rates in Europe run about 2.5 times those in the United States. Environmental concerns run deep in Western Europe, and a long-standing aesthetic objection — that outdoor compressor units and piping mar the appearance of historic districts — has also slowed the spread of cooling technology.

South Korea presents a stark contrast. Urban household air conditioning penetration exceeded 90 percent as of 2023, a level that ranks among the highest in the world. That transformation unfolded over roughly half a century after Goldstar — now LG Electronics — introduced the country's first window-type air conditioner in 1968. Air conditioners have since joined refrigerators and washing machines as one of the three essential home appliances. In an era when heat waves have become disasters, the gap in air conditioning coverage is also a gap in survival.

The first air conditioner was built by Willis Haviland Carrier, a mechanical engineering graduate of Cornell University who joined the Buffalo Forge Company in his mid-twenties.

Carrier did not set out to cool the air. His focus was humidity. In the summer of 1902, he was working at a printing plant in Brooklyn, New York, when he was asked to solve a problem: excess moisture in the air was degrading print quality.

His solution was to spray a fine mist of cold water into the air, causing water vapor to condense onto the droplets — a technique he called dew-point control. The idea of using water to dry the air drew ridicule at the time, but experiments proved it worked. Carrier named the device an "Apparatus for Treating Air," filed a patent application in September 1904 and received the patent in 1906. The rights, however, belonged to his employer, Buffalo Forge.

The technology nearly disappeared. When World War I broke out, Buffalo Forge decided to focus on manufacturing and shut down its air-handling engineering business. Carrier understood the value of what he had invented, left the company and started his own. In 1915, he and a group of colleagues pooled about $35,000 to found Carrier Engineering, which grew into the world's largest manufacturer of cooling systems.

Invoking a Nobel Prize for Carrier is not mere hyperbole. Air conditioning expanded the range of Earth's surface where humans can live. The late Singapore founding prime minister Lee Kuan Yew's praise for the invention is well known. He called air conditioning humanity's greatest invention for Singapore, a country where, he said, people had previously been able to work only in the early morning and at dusk. After taking office in 1965, Lee reportedly made installing air conditioning in every building one of his first priorities.

Carrier's legacy reaches deep into modern semiconductor manufacturing. A clean room, where a single particle or electrostatic discharge can destroy a circuit, requires precise temperature and humidity control — in other words, air-handling technology. The advanced fabrication processes at Samsung Electronics and SK Hynix would not have been possible without the air-conditioning framework Carrier pioneered.

The same holds for the server halls that underpin the internet, pressurized transatlantic aviation and industries that depend on refrigerated distribution. In 1993, Carrier installed precision hygrometers about 9 meters above the floor of the Sistine Chapel to protect Michelangelo's ceiling frescoes — a sign of how far the technology had penetrated even the preservation of art.

Today, Carrier's patents have expired and the underlying technology is in the public domain. The psychrometric formulas he developed — the engineering blueprint for handling moist air — are open to the entire industry, making air conditioning not the property of any single company but a shared infrastructure for humanity.

The inventor's name survives in South Korea's cooling-equipment market. Carrier first took root in the country in 1985, when the American company and Daewoo Group formed a 50-50 joint venture called Daewoo Carrier, which brought room air conditioners and system air conditioners to the domestic market.

The partnership ended in 2000, when the American parent bought out Daewoo's entire stake, renamed the entity Carrier Corporation and assumed independent management. Then in 2011, Otech — a South Korean maker of specialty vehicles and medical devices — absorbed the Korean Carrier subsidiary into its group, creating the current Otech Carrier structure. Today, Otech holds an 80 percent stake and the American Carrier parent retains 20 percent: the founder's brand and technology remain tied to the US headquarters, while a Korean company holds management control.

Otech Carrier produces compressors, air conditioners and air-handling systems at its factory in Gwangju. The company supplies cooling and heating equipment not only for homes and commercial establishments but also for large buildings, hotels, advanced industrial facilities and high-speed trains running at up to 350 kilometers per hour. An invention conceived more than a century ago to tame humidity in a print shop is still running, in one form or another, across South Korea's industrial landscape.