In 2021, I pointed out that within three decades, the number of air conditioning units globally would go from two billion to six billion, creating in the process a vicious circle of more heat, greater electricity demand and higher emissions, unless we can find sustainable ways to stay cooler on our ever-heating planet.
Four years later, the India paradox illustrates how unequal access to refrigeration already causes thousands of deaths every summer: temperatures above 50ºC, overloaded electricity grids and only a quarter of homes with any cooling system. Air conditioning is no longer a luxury; it’s what decides who survives in summer.
The International Energy Agency estimates that in 2022 HVAC consumed 2,100 TWh, 7% of global electricity and 3% of carbon dioxide emissions. If the trend continues, there will be more than 5.5 billion air conditioning units by 2050, and their energy demand could triple. However, it would be enough to adopt standards that force the purchase of the most efficient models already available to cut almost half that expected growth.
Improvements come from several directions. Variable speed compressors, inverters, reduce consumption by up to 40% compared to start-stop equipment, by modulating their power between 25% and 100% and achieving much higher seasonal energy efficiency rates than traditional equipment. Cold weather heat pumps, encouraged in the United States by the Cold-Climate Heat Pump Challenge program, maintain performance coefficients of 2.4 to -15º and use refrigerants with low global warming potential. Start-ups such as Trellis Air separate dehumidification from the cooling cycle using advanced desiccants and could cut electricity bills by up to 90%. In turn, the Global Cooling Prize-winning prototypes combine hybrid cycles and intelligent management to reduce the climate impact of a conventional split fivefold.
Events in South Korea this year anticipate what we will see in other markets: with a penetration close to 100%, sales of air conditioning units rose by more than 50% as households replaced old appliances with much more efficient models, thus relieving a grid that suffers peaks of one hundred gigawatts on the hottest days. The lesson is clear: the sooner countries raise their minimum requirements and provide incentives for replacement, the easier it will be to close the gap between the need for cooling and the capacity of the grid (and the atmosphere) to support it.
The air conditioning of the future must be ultra-efficient, based on low-impact refrigerants and able to dialog with the electricity grid. The technology exists, all that is required is the regulatory will and financial support so that the transition does not leave behind those who need it most. The alternative is an increasingly inhospitable planet, plagued by inefficient and wasteful compressors. Choosing the former literally depends on us starting to change the appliances we buy today.