How Many U.S. Households Don’t Have Air Conditioning? – Energy Institute Blog

With rising adoption, nearly 90% of American homes have air conditioning, but almost 30% in California are still without it.

And, once again, the U.S. is gripped by sweltering heat and humidity. Higher-than-average summer temperatures are everywhere, even in places like Portland, Oregon, which topped 100 degrees last weekend and in Boston, Massachusetts which declared a heat emergency in early August. 

These high temperatures in the Northwest and Northeast are particularly interesting and concerning because these are the few parts of the country where many people do not have air conditioning. The percentage of U.S. households with air conditioning has been steadily increasing for decades, and today nearly 90% of households have some type of air conditioning.

But for today’s post, I want to look at the other 10%. Where are the households without air conditioning? Which states have the most households without? These patterns are important because households without air conditioning are more at risk from dangerous temperature spikes, and because this is where there is likely to be increased adoption in future years.

Keeping it Cool

The map below plots the percentage of households with air conditioning by state. This information comes from the newly-released 2020 Residential Energy Consumption Survey (RECS). Conducted approximately every 4 years by the U.S. Department of Energy, the RECS provides lots of energy-related information about U.S. households. 

As the map indicates, the United States really likes air conditioning. In forty states, 80%+ of households have air conditioning. In thirty-two states, 90%+ have air conditioning, and thirteen states, 95%+ have air conditioning. Despite not being a particularly hot country by international standards, the United States has long vigorously embraced air conditioning. 

Sweating it Out

Still, the map also highlights several states with lower levels of air conditioning. The table below lists the ten states with the lowest percent of households with air conditioning. Alaska is in a category by itself with only 6% of households with air conditioning. Otherwise, the percentage of households with air conditioning ranges from 55% (Washington) to 78% (New Hampshire).

Note: This table was constructed by Lucas Davis (UC Berkeley) using data from the 2020 Residential Energy Consumption Survey. Air conditioning is defined as any type of air conditioning including central air, room air conditioners, and mini-splits. Percentages are calculated using RECS sampling weights.

There is a clear regional pattern here. New England is heavily represented (Vermont, Maine, and New Hampshire), but also the Mountain West (Wyoming and Montana), and the Pacific (Alaska, Hawaii, Washington, Oregon, and California).

These data imply that nationwide there are 14 million households without air conditioning. Of these, 3.7 million are in California. No other state comes close in terms of the total number of households without air conditioning, so the state is likely to be particularly sensitive to health impacts from temperature spikes, and is a state where we are likely to see rapid increases in air conditioning in the coming years. 

Climate Correlation

As you probably already inferred from looking at the map, there is a strong correlation between air conditioning and climate. The scatterplot below explores this correlation using cooling degree days (CDDs), a widely used measure of cooling demand which reflects both the number of hot days as well as the intensity of heat on those days.

Air conditioning is ubiquitous in states with 1500+ cooling degree days per year. This makes sense. There are fixed costs of buying and maintaining an air conditioner, and households choose to bear these costs when they live in a place that exceeds a particular climate threshold.

For the same reason, virtually all of the least air conditioned states have less than 1500 cooling degree days per year. Alaska is again a clear outlier, but Montana, Vermont, Maine, Wyoming, and Oregon, for example, are all relatively cool states where there are few enough hot days each year that many households choose to forego air conditioning. 

Hawaii is a fascinating exception. The average household in Hawaii experiences 3,500 CDDs annually making it the hottest U.S. state by this measure, yet only 59% of households have air conditioning. Readers can weigh in with their preferred explanations, but I suspect the lack of air conditioning in Hawaii has to do with the housing stock. Because it tends not to get very cold in Hawaii, homes are built with less insulation, making air conditioning less effective and more expensive, particularly given Hawaii’s high retail electricity prices.

The Final Frontier for U.S. Air Conditioning

These data were collected just before the record-breaking heat wave experienced in Oregon and Washington during July 2021. It got so hot in the Pacific Northwest that people waited in long lines for a chance to buy an air conditioner, and stores like Home Depot, Lowe’s, and Walmart completely sold out. So even though these data are relatively recent, they already likely understate the current level of air conditioning in some states.

In the United States and other rich countries, household incomes are typically not the limiting factor. Instead, air conditioning adoption in the U.S. is more about climate, and about when and where average temperatures rise high enough to justify the cost and hassle of installing air conditioning. 

This “air conditioning frontier” will continue to move over time with climate change. Since the 1950s, average annual cooling degrees in the United States have increased 30%. Over time, U.S. households are experiencing more hot days and higher intensity of heat on those days, making air conditioning more attractive. The U.S. is already a country with high levels of air conditioning, but there will be fewer and fewer exceptions, with widespread air conditioning even in places that didn’t have it historically.

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Suggested citation: Davis, Lucas. “How Many U.S. Households Don’t Have Air Conditioning?” Energy Institute Blog, UC Berkeley, August 15, 2022, https://energyathaas.wordpress.com/2022/08/15/how-many-u-s-households-dont-have-air-conditioning/