During the same period, average high temperatures in most regions of the U.S. rose between about 2°F and 4°F, according to the National Oceanic and Atmospheric Administration (NOAA). The biggest increases were seen in the Northeast, the Midwest, and the West and Southwest. (The year 2009, it should be noted, was somewhat cooler in the U.S. compared to the years so far this century. But worldwide, the years from 2015 through 2025 were the hottest on record, according to the World Meteorological Organization (WMO).

The amount of electricity needed to run home a/c units surged between 2009 to 2020. Residential a/c in the U.S. consumed an estimated 253.8 billion kWh in 2020, up from 186 billion kWh in 2009, according to the EIA. The average air-conditioned home used about 2,318 kWh for a/c in 2020, up from about 1,980 kWh in 2009.

Spending on the energy to run residential a/c rose as well: In 2020, of all household energy spending in the U.S. — including energy spending by households without air-conditioning — about 14% went toward home a/c, up from about 9.7% in 2009.

All 10 states in which people spent the most per household on home air-conditioning in 2020 were in the South or the West. In Arizona, where about 94% of housing units were air-conditioned in 2020, average spending on energy for a/c among those households was about $658 each. Hawaii, where spending averaged about $638 per household, was second on the list, followed by Florida, where the average was about $492. Texas ($460 per household on average), Louisiana ($452), Nevada ($415), Mississippi ($407), Alabama ($401), Georgia ($390), and South Carolina ($381) round out the top 10.

Residents of Alaska, where only 7% of housing units had a/c in 2020, spent the least per air-conditioned household, an average of about $55, to run that a/c. Across the country, spending on electricity for a/c in 2020 averaged about $299 per air-conditioned household.