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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 spinoff of Lawrence Livermore National Lab has a new 10-point plan to get onto the grid by the 2030s.
One of fusion energy’s newest startups, Inertia Enterprises, is betting that the fastest route to commercial fusion runs through one of the field’s oldest ideas. The company, which raised a $450 million Series A earlier this year, plans to build a power plant based on the laser-driven fusion system pioneered at Lawrence Livermore National Laboratory’s — the only tech yet to have produced more energy from a fusion reaction than it took to initiate it. Now, Inertia has shared its commercialization roadmap exclusively with Heatmap, detailing the 10 near-term capabilities it must demonstrate before this landmark experiment can become a grid-scale power plant by the mid-2030s.
The roadmap offers a route from the national lab’s impressive but commercially impractical fusion demonstrations to an economical power plant capable of producing electricity for the grid. At its core are a set of milestones — mostly aimed at developing cheap, mass-manufacturable components — that Inertia says it must clear before those individual systems can be integrated into a working plant. This road is not necessarily linear, however, as various teams will likely be working on many of these goals simultaneously.
At least the physics of Inertia’s approach are already proven, the startup’s CEO Jeff Lawson told me, pointing to the fusion experiments at Lawrence Livermore’s National Ignition Facility as a proof-of-concept. The lab’s demonstration of net energy gain caps more than six decades and $30 billion (in 2026 dollars) of U.S. fusion research. The remaining challenges, he argued, are all engineering-related, requiring “elbow grease, hard work, and smart people” rather than breakthroughs in fusion science.
"It seems to us like a startup or a commercial company of any variety should be focused on commercializing a proven scientific result, as opposed to actually trying to demonstrate the basic science to begin with," Lawson told me. Basic science, he argues, is better left to national labs and universities, where researchers can pursue "unbounded problems" that don’t align with the expectations and timelines of venture-backed startups.
Indeed, no fusion startup has yet achieved scientific breakeven, the milestone Lawrence Livermore first hit in 2022, and has since repeated numerous times. But leading players such as Commonwealth Fusion Systems and Helion Energy maintain that it’s only a matter of time before they validate the physics behind their own reactor designs, which they claim will be highly cost-competitive.
Lawson, on the other hand, readily acknowledged that Lawrence Livermore’s tech is uneconomical in its current form. His bet is simply that the more predictable path to a commercial reactor is to drive down the cost of the lab’s validated fusion approach, known as inertial confinement. This system relies on high-powered lasers firing at a millimeter-scale pellet of fusion fuel, compressing it to extreme temperatures and pressures until the atoms fuse. Today, the National Ignition Facility makes each individual fusion target by hand, a workable solution given that it only uses about a dozen per year.
That production model, however, isn’t remotely plausible for a grid-scale power plant. Because each fusion reaction lasts just a fraction of a billionth of a second, a commercial facility must fire its lasers at a fresh target about 10 times per second to generate continuous electricity — requiring the production of hundreds of millions of targets each year.
Scaling production to roughly a million pellets per day and making them inexpensive enough for commercial operation without compromising the strength or precision required for fusion ignition is central to Inertia’s roadmap. That includes goals five, seven, eight and nine — industrializing the manufacturing of the carbon shells that hold the fusion fuel, making the thin films that hold those carbon shells both durable and cheap, scaling up and automating fusion target assembly, and speeding up how fast targets are filled with the requisite deuterium-tritium fuel.
The other central focus of the roadmap is the laser system, which will ultimately consist of 1,000 individual units operating in concert to compress and heat the fusion fuel. Key priorities include reducing the system’s cost (goal two), dramatically increasing its firing cadence (goal three), and bolstering its durability to withstand high-intensity operations (goal four). Goal six also complements these efforts, calling for the development of a control system capable of tracking moving fusion targets to precisely align each laser shot.
Goals one and 10 bookend the journey with some broader milestones. The first focuses on increasing the fusion target’s energy gain — the ratio of fusion energy produced to laser energy delivered — to more than 25 times ignition. Today, the National Ignition Facility’s best-performing laser shot has yielded a gain of just over four times what it took to start the reaction. Goal 10 then zooms out to the ultimate objective: integrating all these technologies into a commercially viable power plant that can deliver either electricity or industrial heat to end customers.
To reach that point, Inertia has embarked on an industrial engineering hiring spree, recruiting folks with experience taking complex hardware systems from prototype to mass production, “not unlike the processes that are used in the semiconductor or consumer electronics world,” Lawson explained. The company has been making progress on its component development goals since the beginning of the year, he told me, and expects to announce the successful demonstration of a few of these milestones in the coming months. Lawson ultimately expects Inertia to complete the core components of its laser and target manufacturing systems by the middle of next year.
The team will spend the next two to three years integrating these individual pieces into two fully operational subsystems, a prototype laser system and a target manufacturing line. Around 2030, the company will begin combining those subsystems into a first-of-a-kind fusion power plant, which will also serve as the proving ground for the target chamber, tritium fuel breeding system, and power conversion system that turns fusion heat into electricity. By the middle of the next decade, Inertia aims to be generating power from this first plant, setting the stage for the company to build and connect additional grid-scale commercial power plants.
There are plenty of engineering trade-offs that the company will have to solve for. Take the decision around how to size the target chamber, for example. “If you make it bigger, your walls have an easier time and survive longer, but it’s more expensive. If you make it smaller, your walls have a tougher time because they’re closer to all the heat and energy that the fusion reaction is creating, but now your power plant costs less to build.”
But to Lawson, this represents exactly the type of problem Inertia was built to solve: complex engineering issues that come to the fore once scientists have demonstrated the fundamental physics are sound. He thinks other fusion companies may someday reach this stage, as well — though he’s unwilling to hazard a guess on exactly what approach or startup is best positioned to do so.
“There have been generations of scientists who’ve made their predictions about fusion energy and gotten it wrong,” he told me. “I’m not going to pretend to be smarter than them. All I’m here to say is, just knowing that one did work, we can commercialize it.”