The Washington PostDemocracy Dies in Darkness

Air conditioning remade politics. Now, it’s key to navigating climate change.

As the planet heats up, more will depend on air conditioning to keep cool

A window unit in Houston on July 21. (Brandon Bell/Getty Images)
8 min

Record sustained high temperatures this summer across Europe, the United States and other parts of the world have brought into focus both the benefits and challenges of a global society increasingly dependent on air conditioning. In places where air conditioning is unusual or nonexistent, record-shattering heat is taking a deadly toll.

In much of the United States, air conditioning is fairly ubiquitous, however. The technology grew and developed here in critical ways, and helped shape the politics and history of the United States itself. Its spread across the country — early in D.C., and then across the South and Sun Belt — helped to transform the movement of Americans and regional distribution of political and economic power since World War II. This history shows how changes in the built environment have contributed to the climate crisis and points to the urgency of transforming our buildings to mitigate the effects.

Initially in the early 20th century, air conditioning was developed in the United States to increase economic productivity, by making industrial workplaces and then public spaces such as movie theaters more comfortable for workers and consumers.

This extended to Capitol Hill, where, beginning in the 1920s, Congress, after much debate, appropriated funds for the air conditioning of the U.S. Capitol and nearby House and Senate office buildings. Air conditioning transformed the annual cycle of congressional activity. Before air conditioning, a session of Congress typically lasted for less than 300 days, adjourning by the end of June for the summer. The city was largely deserted from mid-June to September, even in periods of national crisis. Yet, in years after 1938, when air conditioning became operational throughout Capitol Hill, Congress carried its sessions past 300 days and beyond the end of June, when heat waves settled over Washington. Air conditioning curtailed calls for early adjournment.

Air conditioning also transformed daily bureaucratic life in buildings such as the Pentagon, which had the world’s largest air-conditioning plant in a single structure when it opened in 1943. By the 1950s, the General Services Administration found that productivity in government offices increased by 9.5 percent when air conditioning was installed. In Washington, where peak temperatures of 106 degrees and 60 percent humidity had been recorded, air conditioning, “far from being a mere luxury,” proved “essential for normal operating efficiency of personnel.”

The experience of Washington’s many federal employees with air conditioning on the job was a key factor in raising demand for it in other settings, including department stores, theaters, hotels and other commercial sites seeking to draw more consumers.

The rationing of electric power and equipment during World War II initially slowed local adoption of air conditioning in D.C. But as early as 1942, the area’s Potomac Electric Power (Pepco) became the nation’s first summer-peaking utility, meaning that more electricity was used in summer to support air conditioning than was used in winter to power heating equipment. By 1953, Washington had more air conditioning per capita than any other American city. In 1966, about 56 percent of Pepco’s residential customers, including those in the suburbs, had air conditioning of some type; by 1981, that number had risen to nearly 90 percent.

What do we do when air conditioning is a matter of life and death?

Washington’s transformation anticipated air conditioning’s effects across the South and the Sun Belt. Its capacity to mitigate the effects of Southern climate made the South and Southwest attractive for industrial and related demographic growth, shifting economic and political power from its traditional centers on the East Coast and in the Midwest. It made intolerably hot places in the summer habitable and made some of them, from Southern California to Florida, attractive to retirees, new white-collar industries and other year-round newcomers. Improving the indoor environment with air conditioning also enabled the lengthening of the Southern school year by addressing, as one observer noted in 1946, “Unquestionably, one of the largest single obstacles to greater educational advancement in the Deep South.” That is, “the physical conditions under which the faculty and pupils must work.”

In 1940, the most populous states were New York, Pennsylvania and Illinois. Swelling populations in Florida, Texas and California made these the three most populous states by 2015. Between 1940 and 1980, warmer states collectively gained 29 electoral college votes, while the colder states of the Northeast and the Rust Belt lost 31. From 1900 to 1948, only two presidents or vice presidents came from Southern states, but from 1952 through 2004, every winning presidential ticket included at least one such candidate.

Air conditioning has not only shaped the United States, but the world as well. While it is still less widespread in Europe, it is growing there. Japan adopted air conditioning in commercial buildings in Tokyo in the 1930s, and the technology rapidly advanced there, including in homes, from 1960 to 1990. Yet in southern India there was very little air conditioning until the mid-1990s. In China in 1999, air-conditioning units were in about 20 percent of urban households; by 2007 that figure had risen to 80 percent. For equatorial nations such as Singapore and perpetually hot regions like the Persian Gulf, air conditioning has been crucial for development.

A key problem is that air conditioning has always been energy intensive. By 2000, 48 percent of the energy consumed by buildings in the United States (the largest single component) was used for comfort cooling and refrigeration. The release of carbon dioxide and other greenhouse gases into the atmosphere from fossil fuels involved in powering air conditioning has made it central to climate change.

A core dilemma is that as global warming increases, the world will need air conditioning more, but air conditioning is among those technologies that increase global warming.

Its centrality both as a technology essential to global health and comfort and as a contributor to global energy demands and global warming mean that it behooves the world community to develop technologies and policies that will enable us to access this modern mechanism’s benefits while decreasing its inordinate consumption of resources and bad environmental effects.

Just as air conditioning has transformed where and how we live, efforts to mitigate the harms of climate change focus partly in how we approach our built environment. Since the late 1970s, states have recognized the importance of reducing energy consumption in buildings and have adopted policies to reduce air conditioning’s dependence on electricity generated by burning fossil fuels. In the early 21st century, the culture of green building has developed rapidly. Improved material envelopes for buildings, mechanical systems that use less energy and digital monitoring of those systems have reduced energy use. Passive house standards, net-zero carbon buildings and net-zero energy buildings are concepts that have taken hold throughout the developed world, where air-conditioning’s use is highest per capita, with an ever-broadening commitment and cooperation among building owners, architects and engineers, state and local governments and utilities to reduce building energy consumption.

The U.S. government has been active in research and development of energy-efficient buildings since the 1970s. In 2006, the GSA reported that it would use only the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) Green Building Rating System for assessing federal projects. By one account, as of 2018, the United States had decreased energy intensity in federal buildings by 50 percent since 1975. More recently, much is being accomplished through such programs as the Energy Department’s Better Buildings Initiative. And U.S. efforts are only part of a global push for green buildings, from China to Germany to Dubai, among many countries.

It has long been recognized that the climatic effects of reducing building energy use are potentially great. A 2008 report from the U.S. National Science and Technology Council claimed that even at that time, the technology existed to reduce energy consumption in new buildings by about 70 percent relative to conventional norms.

Since then, many more tools for significant energy-use reductions in buildings have been developed, and an international network of information-sharing about them has grown. Today there is widespread consensus that the historic energy and environmental effects of technologies such as air conditioning can be dramatically reduced via solutions that are technically possible, so that our future does not have to repeat our past. This goal is within reach if societies can sustain the political will to encourage their implementation. Technologies such as air conditioning have changed the terrain on which we do politics. We are in an era when politics can help to reshape energy-consuming technologies of the built environment to keep us, and the planet, cool.