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People without air conditioning fare better during blackouts. Here’s why.

I am, in the summer, the human equivalent of a slightly overcooked noodle.
This is especially true in a coastal city like Washington, D.C., where I live. The heat and humidity seep into my bones and I attain a semi-liquid state in which, despite my enthusiasm for hiking and kayaking and swimming and all those other good summer activities, I find myself craving exactly one thing every time I go outside: Air conditioning.
Air conditioners, for better or worse, have become our default solution for extreme heat. When concrete and steel construction replaced regional architecture around the world, air conditioners — where people could afford them — awkwardly, imperfectly filled the spaces left behind by missing local design and materials that would have otherwise helped cope with the weather. And as the world gets hotter, ACs are growing more and more popular: In India, where I mostly grew up without an AC, sales of ACs have skyrocketed over the past decade from three million units in 2013 to an expected 9.7 million this year.
But there is, of course, a catch. As vernacular architecture disappears, so too does vernacular knowledge; many of us, bowing to our cooling-machine gods, have forgotten how to deal with the heat.
Air conditioning has an odd side effect: It makes us dependent. In a 2021 study from Georgia Tech’s Urban Climate Lab, which modeled indoor heat across Atlanta, Phoenix, and Detroit during heat waves, researchers found that people without air conditioning would fare better during a blackout because they’d be more likely to take other measures to help deal with the heat. These are simple moves, like drinking more water and using curtains to keep their rooms dark and cool, whereas people with air conditioning might put too much faith in their appliances — and be entirely unprepared for those appliances to stop working.
“I think a combined blackout and heat wave is the most deadly climate risk we’re confronting right now,” said Brian Stone Jr., director of the Urban Climate Lab and a Professor in the School of City and Regional Planning at Georgia Tech. “A blackout situation really kind of inverts the traditional risk pyramid. If you don’t have air conditioning in your house, you probably have greater heat resilience. Those of us who have air conditioning whenever we want it are going to be more susceptible.”
Heat waves put extreme stress on power grids, and blackouts are increasingly common as summers get hotter. If more people buy more air conditioners without any work being done to shore up the grid (and, believe me, the grid badly needs shoring up), that extra stress could lead to quicker, more common grid failures. It’s unfortunately easy to imagine just how dangerous a grid failure can be: A major blackout during a heat wave would be the inverse of the Texas blackout during the winter of 2021, when hundreds of Texans died of hypothermia in their own homes.
For someone in a house without an air conditioner, a blackout during a heat wave probably wouldn’t affect the temperature inside much; someone who does have one, however, will inevitably find their house heating up beyond a point they were prepared for. As Rebecca Leber pointed out in Vox, early-season heat waves are dangerous because our bodies aren’t prepared for the heat. The sudden loss of air conditioning for someone used to it is dangerous for the same reason.
Our built environment, like a natural ecosystem, is the sum total of many pieces fitting together, and not all of them fit perfectly. Air conditioners are the perfect example: They aren’t universally good at cooling our buildings down, especially if those buildings weren’t built with air conditioning in mind — they often lack proper insulation, for example, which means cooled air will escape a room quickly. That means air conditioners will have to work harder to cool the air, which both further heats up the air outside and places more stress on the grid. When the built ecosystem fails, its human inhabitants inevitably suffer.
Last week, I wrote about a study out of Portland, Oregon, that measured how hot the units in three public-housing developments got during the summer of 2022. To the surprise of the researchers conducting that study, the units with air conditioners were not much cooler than those that didn’t have them. There were a few reasons for this: first, running an air conditioner is expensive, and residents with air conditioners would often turn the temperature up to save on electricity costs. Second, the buildings weren’t designed for air conditioning, so the apartments couldn’t retain cooled air very well.
Third, and most importantly, the residents who didn’t have air conditioners were both more cognizant of heat dangers and more likely to take other steps to cool their spaces down; they retained, in other words, a sort of vernacular knowledge of how to deal with the heat.
“The residents who don’t have air conditioners go to great lengths to keep their homes cool,” said Dana Hellman, a program manager at CAPA Strategies, the climate consultancy that ran the Portland study for the city. “For example, they made DIY insulation for their windows or kept all their lights off or their curtains closed all day long. It’s burdensome, but it might be leveling the field a little bit.”
Which isn’t to say that air conditioners should be abandoned wholesale. If indoor temperatures rise too much, everyone is at risk of heat stroke. Many cities, including Portland, operate cooling centers for residents to go to during extreme heat events. But none of those cities mandate that those centers have some sort of backup power option, and even if they did there aren’t nearly enough centers to serve every resident.
As with climate change more broadly, there are obvious equity issues here: The people who are most likely to use cooling centers are the people who are most likely vulnerable in other ways, as well. More well-off residents can afford to pay for an air conditioner, its associated costs, and possibly also a backup generator to help them ride out a heat wave in the comfort of their own homes; many cooling centers are understaffed and under-resourced, which raises safety concerns for residents who then have to choose whether to stay home or potentially put themselves at risk for the sake of finding relief from the heat.
So what should we do as the world continues to heat up?
We can start with the long, hard task of adapting the grid to keep us safe during heat waves, a fix that Stone points out is decades overdue. “Back in the 90s, the idea was that we’d be successful in reducing global emissions and wouldn’t need to adapt [to global warming],” Stone said. “If we had acknowledged to ourselves that it was going to be a 20 to 50 year project just to start adapting, we might have been more attuned to the fact that the electrical grid is a life support system for us when it is too hot outside to be healthy. But that’s been a slow realization.”
In Portland, the housing authority has a program to provide public housing residents with free air conditioners. But there are other forms of adaptation, too: Stone and his colleagues found that cool roofs, which reflect more sunlight than traditional roofs, can lower ambient temperatures by 1 to 1.5 degrees Celsius. Urban tree cover, which throws potentially life-saving shade onto houses and roads alike, can also go a long way towards cooling things down.
Most important, however, is actually going to be changing the way we interact with heat. Education — getting people to take heat waves as seriously as, say, a hurricane or wildfire — is just as important as modifying our built environment. Perhaps we'll all, as Morgan Meaker wrote in Wired last year, take a leaf out of the Spanish playbook and adopt the siesta (an idea that I personally endorse), or learn to live in the dark caves of our curtain-darkened apartments in the peak of summer.
I may even start turning up my AC to let my body acclimatize to its natural state of noodle. Whatever the solution, heat must re-enter our vernacular: not just as something we mechanically force out of our homes, but as something we figure out how to live with.
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The Iran war has been a gift to the country’s vehicle, solar, and battery business.
This is Heatmap Daily, a weekday evening digest written by our executive editor.
Happy Monday and welcome back. For months now, we’ve been talking about how the U.S. and Israel’s war in Iran has been a boon for electric vehicles, clean energy, and (unfortunately) coal.
But today we got data that confirms: This clean energy export boom is not just a side story. It is one of the brighter spots in the overall Chinese economy, which remains the world’s second largest.
According to economic data released on Monday, China grew 4.5% during the summer quarter as compared to the quarter from a year earlier. That means the country will likely hit its growth target this year, albeit on the low end.
The country’s economic expansion wasn’t driven by domestic consumption, however. Consumer confidence remains low, and residential investment has yet to return after the property crash earlier this decade.
Instead, booming exports are now driving China’s economy. Exports were more than 36% higher in September than a year earlier, driven by chips, ships, electric vehicles, and solar panels and batteries. The country will likely record its biggest trade surplus ever this year.
Some of those categories are clearly flourishing thanks to the global AI boom — think chips and even batteries. But the preponderance of vehicle exports suggests surging oil prices aren’t hurting. Sales of ‘new energy vehicles,’ a category that includes 100% electric vehicles and plug-in hybrids, were up more than 13% on a year-over-year basis in September, according to the Chinese car manufacturer’s trade group. But exports of these vehicles are booming. Battery electric vehicles were up 130% last month compared to the same period in 2025, and plug-in hybrid exports were up more than 200%.
It’s interesting to consider how much the Chinese and U.S. economy are mirroring each other at this moment. Americans are dealing with a remarkable investment boom, which is buoying the labor market and stubbornly maintaining high inflationary pressure. China is struggling with deflation, and exports are its quickest path to growth. (Consumer sentiment in both countries, interestingly, seems to be in the doldrums, even though American consumers appear to be in much better shape.)
When thinking about what artificial intelligence could do for the United States over the next decade, some subject-matter prognosticators (and even some Anthropic employees) imagine a world of 4%, 5%, or even 7% GDP growth. Such a growth rate is difficult even to envision in the modern era, of course, and it seems like it could propel the U.S. economy to staggering prosperity.
I know better than to make a prediction about where we’re headed. But amateur economic commentators should keep China in mind, too: a country that dominates along many technological axes, but where the standard economic math of supply, demand, and consumer sentiment still holds. Except if the United States economy were to stumble, no exterior source of demand will come to our rescue.
Endurance Energy hoped its generator would run for a full year, but the team isn’t afraid of the “error” in “trial and error.”
About 300 miles off the Oregon coast, a mile beneath the ocean’s surface, a startup just drilled the world’s first subsea geothermal well. And for a grand total of exactly 8.7 seconds, its prototype power plant generated about 2 kilowatts of net power. It wasn’t quite the result the Seattle-based Endurance Energy was hoping for — the company’s goal was to run its 100-kilowatt generator for a full year. But it’s not nothing.
“We really proved with this mission that a geothermal well could be drilled and completed on the seafloor, and doing that within 21 months of the company existing I think is really a testament to our pace of progress,” Endurance CEO Andrew Redd told me.
A former SpaceX engineer — as so many climate tech founders seem to be — Redd appears quite comfortable with the rapid trial-and-error cycles that hard tech startups often demand. Or as he stated in the company’s press release, which provides a refreshingly frank account of what this first test did and didn’t accomplish, “We follow the adage ‘make it exist, then make it good.’”
Investors seem to be buying it. In June, the startup raised a $54 million Series A, led by Peter Thiel’s Founders Fund — Endurance’s second funding round in less than two years of existence. Still, the team certainly has their work cut out for them. The ocean is a notoriously difficult operating environment: Saltwater is corrosive and offshore infrastructure is difficult and expensive to build, maintain, and repair.
Indeed, Endurance spent the first 11 days of its three-week stint at sea debugging its drill, which the team had never operated underwater before. But with a vessel chartered and a locked-in deployment date, the company couldn’t afford to wait for everything to work out perfectly. “We were still working on that generator hours before it got on the seafloor,” Redd told me. He’s used to that sort of thing, though, comparing it to making final tweaks to rockets already sitting on the launchpad. “That’s kind of the name of the game,” he said.
The trial took place at Axial Seamount, an active underwater volcano and the only place in the world with a cluster of hydrothermal vents connected to shore by fiber optic cable, which allows the Endurance team to monitor and control its system in real time from Seattle. While this was the company’s fifth deep-sea mission, it was the team’s first attempt to actually drill their own well.
After lowering their drill about a mile below the surface, the team bored two holes and turned the second into a well about 2 inches wide, lining it with pipe and sealing it with cement. But after losing so much time to debugging, the team only managed to drill about 52 feet deep — far short of its original 200-foot target.
Water then flowed up the well at about 260 degrees Celsius (around 500 degrees Fahrenheit), but the narrow borehole proved too restrictive to deliver enough heat for the generator to operate. So the team pivoted, connecting the generator directly to a naturally flowing, hotter hydrothermal vent instead. The generator then ran for a total of 29 seconds, producing about 2 kilowatts of net power for 8.7 seconds. That represents the total electricity the turbine generated, minus the 7 to 8 kilowatts needed to run its supporting components, such as the refrigerant pump and other onboard equipment.
Then a software glitch triggered the onboard battery safety system, which shut down the plant. When the team tried to restart the system, the power cable feeding the refrigerant pump failed, leaving the pump unable to restart. That was the end of the road. The mission wrapped up after three weeks at sea, a far shorter run than the team had hoped.
“The success criteria would be if we had left with the generator still on the seafloor; that would have been an example of sustained net power, and we didn’t get there,” Redd told me. Instead, the team brought the system back to Endurance’s Seattle headquarters, where it’s fixing the software as well as refurbishing and upgrading the hardware — which includes changing how it builds and tests subsea cables — to prepare for another mission sometime this winter. This time, the goal will be to generate sustained power from a much deeper well.
The team will need to demonstrate progress soon to keep its next major milestone on track: a planned 2-megawatt deployment off the coast of Tonga by the end of 2027. The project aims to supply electricity directly to the Tongan grid, which today is heavily dependent on expensive, imported diesel. Redd expects subsea geothermal to be cost-competitive with that fuel in this first pilot.
Getting there, however, is a formidable engineering challenge. While it’s long been a subject of academic curiosity, no one prior to Endurance had ever drilled an offshore geothermal well before, meaning the team can’t simply transplant existing land-based technology to the seafloor. “Every component that you would use terrestrially now needs to be either modified or built completely from scratch,” Redd explained. “And so you multiply that across every component required to make these kinds of infrastructure projects happen, and it’s a lot of work.”
No kidding. But if Endurance can pull it off, Redd sees this resource as “the perfect energy source for the future.” A conference paper presented by the geoscience company Viridien last year estimates that offshore geothermal resources worldwide could yield about 6 terawatts of recoverable electric power — nearly twice the world’s current continuous electricity output.
“We can access terawatts of power. There’s no fuel. We can site next to extremely large cities around the Pacific. We have no surface presence,” Redd said, ticking off the advantages. Plus, the three necessary ingredients for a high-quality geothermal well — permeable rock, high heat, and water — are widely accessible offshore, he added. Eventually, he expects subsea geothermal to undercut natural gas in Endurance’s target markets: electricity grids, industrial facilities, and data centers across the Pacific Islands, the U.S. West Coast, and Northeast Asia, all of which sit along the undersea volcanic zone known as the “Ring of Fire.”
The way Redd sees it, advances in subsea technology pioneered by the offshore wind, oil, and gas industries have cleared much of the technological path to making underwater geothermal a viable clean energy resource. In his view, what’s been missing is simply the ambition to chase the opportunity in the private market. SpaceX, he said, really proved what’s possible for a scrappy startup to achieve.
“It is quite new at industrial scale for a small company with a bunch of fairly young people to go after something like this,” he told me. “Before SpaceX went to launch a rocket as a private company, no one thought you could get to orbit as a private company. And so that has really seeded this ambition.”
On Greenland’s deepsea mining ban, Indonesia floating nuclear, and a solar boom
Current conditions: Hurricane Trudy has weakened from its peak as a Category 2 storm but still threatens up to 8 inches of rain as it swirls off Baja California • A nor’easter is howling through the Mid-Atlantic this week, hammering the coast with winds of up to 70 miles per hour • A humid overcast has settled over Paris this week as French authorities struggle to regain control after protests over living costs gave way to anarchic riots.
At least 47 major data center projects have been delayed, withdrawn, or blocked so far this year, according to data the regulatory intelligence service RegLayer shared with the Financial Times — and that may be a “conservative estimate.” Just 35% of planned data centers are “credible,” analysts told the newspaper, as more than 1,000 communities across the United States now have restrictions on artificial intelligence infrastructure. The data comes as investors look increasingly jittery about AI following ChatGPT-maker OpenAI’s missing a key revenue metric this year.
Those findings stand in contrast with the numbers from our data service, Heatmap Pro. Based on our research, at least 107 projects faced cancellation so far this year, putting 2026 on track to beat last year, which saw 108 proposals nixed.
Unless you’re living off the grid and away from any social media (if so, I’m jealous), then you can probably surmise that not-in-my-backyard opposition prevails in many such cases against proposed data centers. That makes selling would-be neighbors on the projects critical. New polling by the advocacy group GoodPower found that a binding promise to protect local electricity rates boosts support for the projects upward by as much as 14 points. Such a pledge worked primarily on the 78% of voters who distrust data centers. Another potential winner: Pair a data center with renewables. At least 46% of respondents to the poll said their support would increase if a project were powered by renewables. The survey spoke to 2,610 registered voters last month and oversampled in states with at least 200 data centers completed: Arizona, Georgia, Indiana, Pennsylvania, Texas, and Virginia.
Greenland wants to find ways to exploit its mineral riches in hopes of generating enough income from industries other than fishing and tourism to eventually wean off subsidies from the governments of Denmark and the European Union. Earlier this month, as you may recall, the self-governing Danish island gave a project the green light. But the government in Nuuk doesn’t want miners harvesting metals from the seabed surrounding the Arctic island, which are fertile fishing grounds and could, in theory, lead to mineral production without meaningful infrastructure to create jobs for Greenlandic people. Last week, the Greenlandic Parliament adopted a resolution requiring the government to draft legislation banning deep-sea mining. All members present voted to approve the proposal, according to Sermitsiaq, a leading newspaper in Nuuk. The ban would, if adopted, last until the end of 2029, with the possibility of an extension for two years at a time.
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Long before the race for small modular reactors kicked off, Russia launched a floating nuclear power station and sailed the vessel up to the Arctic to power a small town. Now, as you may recall, the state-owned Russian nuclear company Rosatom is making plans to build more floating nuclear plants, and it has a major nuclear newcomer nation as an offtaker. Last week, NucNet reported, Rosatom announced a deal with Indonesia’s state-owned PT Pembangkit Listrik Nuklir to supply electricity to northern Indonesia from at least two floating nuclear plants with a capacity of 200 megawatts each.

Over the past decade, small-scale and rooftop solar systems increased from 18,812 gigawatt-hours to 92,979 gigawatt-hours, an increase of over 394%. That’s according to a new analysis from the Energy Information Administration, which found that California, Arizona, Texas, Florida are the regions with the most abundant solar resources. Even though the state has worse solar resources in general, New York ranked fifth as a result of growing capacity. Still, the rate of growth in generation has slowed over the past three years. l
The Trump administration is pulling out all the stops for Alaskans who want to drill and transport fossil fuels, mine minerals, and log trees. Now he’s easing rules on hunters. A new final rule from the National Park Service has revived a hunting method the Biden administration banned in 2024: Baiting bears with doughnuts soaked in bacon grease. Hunters use the baits to lure bears to close range before shooting them. “Some hunters prefer to use strong-smelling, high-calorie foods like pastries, doughnuts, meat scraps or fish remains to lure bears from miles away,” The New York Times reported. “But some conservationists say the practice is unethical and risks making the bears accustomed to human food, which could endanger people.”