Global A.C. use to spike as incomes rise

Above, AC units and bags for sale in New Delhi, India. (Credit: iStockphoto)

As incomes rise around the world, people get to live more comfortably, which includes being able to afford air conditioning.

Staying cool is good, but the demand for more AC will also cause consumers to use more electricity causing stress on energy prices, infrastructure, and environmental policy, according to a new study.

The study introduces a new energy model that examines the relationship among climate, income growth, and air conditioning adoption.

Reported in the Proceedings of the National Academy of Sciences, the findings point to significant potential global impacts from air conditioning usage and the authors call for action now.

“In the near future, over a billion people in Africa, Brazil, India, Indonesia, Mexico, and other low and middle income countries will be able to purchase their first air conditioner resulting in a massive increase in energy demand,” says study coauthor Paul Gertler, a professor at the University of California, Berkeley’s Haas School of Business.

“Now is the time for the public and private sectors to collaborate and develop infrastructures capable of accommodating rising demand, as well build air conditioners that are more energy efficient and more affordable for poorer populations.

“In China alone, sales of air conditioners have nearly doubled over the last five years,” says coauthor Professor Lucas Davis. “Meeting the increased demand for electricity in the future will be an enormous challenge requiring trillions of dollars of infrastructure investments and potentially resulting in billions of tons of increased carbon dioxide emissions.”

Mexico’s climates

Davis and Gertler analyzed data on 27,000 households in Mexico, a country with varied climates ranging from those that are hot, humid, and tropical to dry deserts and high-altitude plateaus. At all income levels in the cool areas of the country, the data showed little air conditioning usage present, 10 percent or less.

In the warm areas, air conditioning increases steadily with income—2.7 percent per $1,000 of annual household income—to reach almost 80 percent.

Assuming conservative increases in income and temperature increases, the model predicts near universal saturation of air conditioning in all warm areas within just a few decades—primarily correlated to income growth.

In Mexico, this combination of a massive increase in air conditioning adoption and increased use due to rising temperatures means that energy expenditures are forecast to increase by 81 percent. However, Gertler and Davis contend that future technological changes and higher electricity prices will likely lower this estimate.

‘Cooling degree days’

The global impact of increased air conditioning heats up even further when population is factored in. The study compared population, annual gross domestic product per capita (GDP in thousands), and the annual “cooling degree days” or CDDs in 12 countries with mostly warmer climates.


CDDs are units used to measure energy demand. A cooling degree day is the number of degrees that a day’s average temperature is above 65º Fahrenheit and people start to use air conditioning to cool their buildings. In other words, cooling degree days are calculated by subtracting 65 from a day’s average temperature.

In India, for example, with a population of 1.2 billion, the potential demand for cooling is 12 times that of the United States with a population of 316 million. Why? Because India’s population is four times the US population and its annual CDDs per person (3,120) is three times more than that of the US annual CDDs (882).

India’s infrastructure already has been unable to accommodate surges in energy consumption resulting in brownouts and blackouts.

The researchers contend that while more energy-efficient air conditioners and low-carbon electricity generation could help mitigate environmental concerns, the future of electricity prices will also depend on the progress of other factors.

“A substantial increase in electricity prices resulting, for example, from carbon legislation, would slow both adoption and use,” writes Davis.

Source: UC Berkeley