King County's cooling divide: New data maps our AC haves and have-nots

In 2018, I reported that Seattle was the least air-conditioned large metro in the U.S. - a title we held until San Francisco recently overtook us. But those numbers came with a significant caveat: The data we relied on, from the U.S. Census Bureau's American Housing Survey, tracked only the nation's large metropolitan areas. This approach overlooked vast swaths of the country, including all of Alaska.

Now we have the complete picture. The Census Bureau this month released an experimental data set of local air-conditioning estimates that, by combining survey data with modeling, maps estimates of homes with AC units down to the census-tract level nationwide for the year 2023.

Census tracts generally have a population between 1,200 and 8,000 people, with an optimal size of 4,000. In dense urban areas like Seattle, tracts are relatively small geographic areas - the city of Seattle comprises 177 tracts as of the 2020 Census. In rural and sparsely populated areas, though, they typically cover a larger land area.

Zoom out, and Seattle's lack of cooling doesn't look as exceptional. The data shows Alaska accounted for the 150 least air-conditioned census tracts in the country. Then there were some tracts in coastal California, Hawaiʻi and Oregon before we finally reached the least air-conditioned tract in Washington.

That tract was not in the Seattle area - it was located on the waterfront in downtown Bellingham, where 22% of homes had AC. Next were two tracts in downtown Everett, both at around 23%. Then we finally hit the tracts in King County with the lowest AC rates.

Within King County, where overall coverage was 53% - the 10-lowest among Washington's 39 counties - the data revealed a massive cooling divide.

The county's least air-conditioned tract was in the heart of the University District, encompassing a large chunk of The Ave, where only 279 of its 1,190 homes, about 23%, had AC.

Demographically, this tract was fairly typical of undercooled areas in King County. A low median household income - around $24,400 - made air-conditioning units and higher electricity bills less affordable to residents. The densely populated area also had a high percentage of renters who likely could not make structural modifications to their living spaces, and many of the older brick apartment buildings would be difficult to retrofit for AC.

This tract, largely populated by University of Washington students, had a median age of just 22. That's fortunate from a public health perspective, as younger people are generally better equipped to withstand extreme heat than older people.

Rounding out the county's bottom five tracts were two more in the U District, one in Auburn near the municipal airport, and another in Seattle covering parts of the Chinatown International District and Pioneer Square. Coverage in these neighborhoods hovered between 24% and 26%, leaving most residents to muddle through heat waves with cold showers and oscillating fans.

Heading across Lake Washington revealed an entirely different climate reality. The 50 census tracts in King County with the highest concentration of cooled homes were all on the Eastside and in eastern King County, including 32 tracts where 80% or more of homes were air-conditioned.

Unlike the undercooled urban core, these affluent suburban clusters were predominantly composed of newer, owner-occupied single-family homes. Much of the Eastside's housing was built when central air was already standard, making a heat pump installation in a modern house a relatively simple upgrade.

King County's most air-conditioned tract was in Snoqualmie, running south of Snoqualmie Parkway to the city's historic downtown. There, 96% of the 2,052 occupied homes had AC. This tract's median household income was around $183,800. About 88% of households were married couples, and 93% of homes were owner-occupied.

For context, the most air-conditioned neighborhood within Seattle city limits was well-heeled Laurelhurst, at 74%.

Statewide, around 67% of Washington homes were air-conditioned, the lowest rate among the 48 contiguous states and Washington, D.C. Three states tied for the highest rate of nearly 100% - Florida, Oklahoma and Delaware. Alaska had far and away the lowest rate at just 7%, followed by Hawaiʻi at 57%.

While it may be fun to dive into these numbers on air-conditioning rates, the Census Bureau produced this data for a highly practical reason. Air conditioning is lifesaving infrastructure during extreme heat waves, especially for older adults. With these estimates, city planners may be able to accurately pinpoint where emergency cooling resources are most needed.

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This story was originally published June 15, 2026 at 6:34 AM.