Broken AC is leaving millions of households exposed to extreme heat, while cooling repairs can average about $2,200.
For millions of households, having an air conditioner doesn’t necessarily mean staying cool.
Over 13 million U.S. households said their homes became uncomfortably hot for at least 24 hours in 2023, according to an analysis released on Wednesday from the Harvard Joint Center for Housing Studies. Among households that had air conditioning but still experienced excessive indoor heat, 42% cited an equipment breakdown—the most common reason by far.
The findings land as another round of punishing late-summer heat bears down in some parts of the country. Temperatures in the Southwest and Southern Plains are expected to reached near-record highs through Friday as a powerful heat dome lingers through the first week of the start of meteorological fall.
Extreme heat can make functioning cooling equipment a necessity, but the cost of keeping that equipment working can come with a price tag out of reach for a majority of Americans.
Nearly 8 million households had at least one cooling-related repair in 2023, at an average estimated cost of about $2,200 per unit, according to a separate 2025 analysis from the Federal Reserve Bank of Philadelphia.
Meanwhile, half of U.S. adults told the Federal Reserve that the largest emergency expense they could handle using only their savings was less than $2,000.
The hidden cost of staying cool
The Harvard findings underscore the difficulty of combating hotter and longer summers.
Relatively few households blamed the direct cost of cooling for their uncomfortable indoor temperatures, even as utility bills climb. From 2018 to 2024, the average annual cost of cooling a home increased by more than $105 in 376 counties across Alabama, Arizona, Arkansas, California, Florida, Hawaii, Louisiana, Mississippi, Nevada, Oklahoma, and Texas, according to a new Duke University analysis.
But affordability can affect cooling in less obvious ways. Air-conditioning and HVAC systems need to be serviced, repaired, and eventually replaced, while insulation and other parts of a home can determine how well it holds a comfortable temperature.
The Energy Information Administration projects the cost of electricity to continue to climb over the next quarter-century in the U.S. (U.S. Energy Information Administration) Those investments can vary dramatically depending on household income.
In 2023, homeowners earning more than $172,000 spent nearly three times as much replacing systems and equipment as homeowners earning less than $37,500, according to Harvard.
The researchers note that inadequate cooling can stem from several factors, including broken or inefficient HVAC systems, high cooling costs, and poor insulation.
In other words, two homeowners can both technically “have AC” while having very different protection from extreme heat. One may have a newer system, better insulation, and the savings to cover a sudden and unexpected repair. Another may be relying on aging equipment in a less efficient home without thousands of dollars readily available if it fails.
As summers grow hotter, that difference can become more consequential.
Renters are even more likely to get too hot
The burden is not limited to homeowners, either.
Renters were substantially more likely to report uncomfortable indoor heat than homeowners: 13.7% of renters experienced it, compared with 8% of homeowners. Rates were also higher among households in multifamily buildings and manufactured homes than among those in single-family houses.
And renters with AC who experienced excessive heat were more likely than homeowners to report that their equipment simply did not provide enough cooling capacity: 17.7% of renters cited inadequate cooling, compared with 11.6% of homeowners.
That can leave renters facing a different version of the same vulnerability. Homeowners generally decide whether and when to repair or replace their own systems. Renters may have less control over the major systems and other factors that determine how effectively their homes stay cool.
Some households still have no AC
Then there are households without cooling equipment at all.
About 6.9% of U.S. households had no air conditioning, according to the Harvard analysis. Those households were almost twice as likely to experience uncomfortable heat as households with AC—17.5% versus 9.4%.
That does not mean every home without AC needs it. More than three-quarters of households without air conditioning said their homes held temperatures very well or somewhat well without a cooling device.
But nearly a quarter said their homes did not stay cool well—or at all.
Harvard researchers argue that the challenge will become more urgent as heat waves become more frequent and geographically widespread, particularly in communities where households have fewer financial resources and housing is most in need of repairs.