Americans have been cranking up the AC as heatwaves become more frequent. Nearly 90% of American homes are using some form of air conditioning, according to recently released data from the US Energy Information Administration (EIA).
For comparison, less than 10% of households in Europe have an AC unit—though that number is predicted to increase as extreme summer temperatures like the ones currently scorching the region become more common.
Hotter and longer summers mean dangerous conditions for people exposed to extreme heat and humidity. Low-income and other vulnerable populations are particularly at risk of heat stress, heat stroke, and death without some form of cooling. At the same time, higher AC usage is straining the electrical grid and boosting carbon emissions that will further contribute to global warming.
More than 100 million Americans are currently under heat warnings due to heatwaves. A study by Climate Central found that average summer temperatures have increased by 2°F or more in over half of the locations it surveyed across the US between 1970 and 2021. States in the western and southwestern US recorded the greatest increases. Summer is also lasting longer, with 81% of locations experiencing at least an extra week, according to the study. Since 1993, air conditioning usage has increased by 28%, EIA data show.
EIA data also show more households are investing in central air systems, which are several times more popular than window or wall units.
Many Americans with a central AC system set the temperature and forget about it. That’s how central AC is used in over 40% of homes. A much smaller but growing share—16%—use a smart thermostat to adjust the temperature.
Americans have a growing number of options to keep cool aside from installing a central AC system. Geothermal heat pumps are one of the most energy efficient forms of air conditioning, according to the EPA. Unlike traditional heat pumps, which collect heat from the air and eject it outside the home, the geothermal version absorbs cooler temperatures from the ground to circulate inside.
Evaporative air coolers use water to bring down hot air temperatures, and are less energy-intensive and cheaper than central AC. Planting trees and other vegetation also provides natural evaporative cooling and shade.
For those who already have central AC, there are ways to get it to run better. For example, making sure there are no leaks in the duct system helps air conditioners perform at their rated efficiency. And generally, a well insulated home with well-sealed windows will help with overall cooling.