As temperatures blew past 100°F in cities across Europe last week, it was difficult to tell what was generating more hot air: the weather or the discourse around the right way to endure it.

On the western side of the Atlantic, the answer was almost uniformly obvious: air conditioning. Just around 20 per cent of European households have air conditioning, compared to 90 per cent in the US. Even public buildings — including vital ones like schools and hospitals — often go without air conditioning in Europe. Primarily, it’s not because they can’t afford them but because, for some reason, many people there think there’s something inherently wrong with what the French call “climatisation”.

The very idea of air conditioning, to many Europeans, is an example of maladaptation: “a false solution that makes the problem worse” – in the words of far-left French politician Jean-Luc Mélenchon. Better to adapt for those sweltering days by closing the shutters and blinds during the day, staying in the shade, drinking plenty of water, and maybe planting a tree. Air conditioning? You won’t find that mentioned in many government heat advisories.

From my (heavily) air-conditioned office in New York, it almost feels like sport to watch the X fights play out as smug Americans dunk on their European counterparts — did you know you need a doctor’s note to air-condition your home in Geneva? — and Europeans, presumably tweeting from inside their darkened chateaux, give it right back. It’s like the World Cup, except World Cup matches actually end.

But the stakes around extreme heat and the lack of air conditioning aren’t funny at all. Europe has more heat deaths per capita than any other continent, and, in 2022, alone, more than 61,000 Europeans died from heat-related causes. Early estimates suggest there were at least 1,000 excess deaths during the three worst days of the heat wave in France last week, with overbooked mortuary owners turning away family members who had lost loved ones to the heat.

The reality is that it’s only going to get worse. Europe is already the fastest-warming continent in the world, heating at roughly twice the rate of the global average since the 1980s. More than two-thirds of Europe’s most severe heat waves since 1950 have come since 2000, and, by 2050, about half the continent’s population could face high or very high heat-stress risk every summer. And while Europe has taken climate change more seriously than any other region, the next 20-plus years of warming are largely locked in, meaning that Europe alone can’t mitigate its way out of ever more intense heat waves. It has no choice but to adapt.

And adaptation will require air conditioning — full stop. There is no technology more effective at turning a deadly heat wave into a survivable one. But, for that to happen, both sides of the Atlantic need to shed the political and cultural baggage they’ve loaded onto AC units. Air conditioning is not the moral failing Europe imagines, nor the emblem of freedom and the good life that America takes it for. Air conditioning is a normal technology — a machine that does a useful job at a manageable cost, like a refrigerator or a furnace — and, in a world that is only going to become hotter, it is a lifesaving one.

Make air conditioning normal again

To find the way out of the AC wars, it helps to borrow an idea from another technology people have strong feelings about: artificial intelligence. While much of Silicon Valley spent years insisting AI would either deliver paradise or end the species, two Princeton computer scientists, Arvind Narayanan and Sayash Kapoor, offered an alternative last April. AI, they argued, is a normal technology. Normal did not mean unimportant; even world-remaking tools like electricity and the internet are “normal” in their conception, adopted gradually and improved over time rather than arriving to void the old rulebook. Normal technology is neither a saviour nor a demon; it is simply a machine that does a job. And air conditioning has almost never been seen that way.

Its effectiveness, at least, should not be in doubt. In a landmark study tracking US mortality across the entire century, the economist Alan Barreca and his colleagues found that the chance of dying on an extremely hot day fell by about 80 per cent from the years in the 1900-to-1959 stretch to the decades that followed. Days above 90°F had once been mass-casualty events; by the back half of the 20th century, they were responsible for roughly 600 deaths a year, down from the 3,600 who would have died had heat remained as lethal as it was before broader use of air conditioning. And it is the spread of that technology, the authors concluded, that explains essentially the entire decline — almost none of it began before 1960, the exact moment home AC started its march across the country. And globally, the Lancet Countdown estimated that, in 2019, air conditioning averted 195,000 heat-related deaths among people over 65, who are most vulnerable to heat.

To which Europeans might say the following: What about carbon? Air conditioning runs on electricity, and it can add to climate change depending on the dirtiness of the grid it’s drawing from. More air conditioning, more climate change — that’s the maladaptation AC critics see.

But what’s true of air conditioning is also true of any use of energy. Currently, space cooling accounts for just 0.8 per cent of the energy EU households consume, compared to 77 per cent for heating. Cooling is smaller than heating at a ratio of nearly 100 to 1, yet, outside special situations like the 2022-23 Ukraine-related energy crisis, you rarely hear proposals to cap winter thermostat levels or denunciations of radiators as a decadent indulgence. Air conditioning is placed in a special moral category, possibly due to its relative newness or simply because Americans love it so much.

Even if Europe did decide to increase air conditioning coverage significantly, and the energy continued to come from a similar distribution of carbon-generating sources, the carbon output would be minimal. If Europe were to double air conditioning to 40 per cent of households by 2050, according to a 2023 paper, the added carbon would represent just three-tenths of one per cent of the region’s current emissions. Get closer to a level comparable to the US or Japan, and the effect on emissions would still be fairly low.

It won’t be easy, necessarily. As Robinson Meyer at Heatmap wrote this week, the well-sealed windows common in many European cities outside the south make window units difficult to install. But then, decarbonising Europe’s grid was also difficult, and the region has done so effectively. Renewables now generate nearly half of EU electricity, and the bloc has committed to cutting emissions 90 per cent relative to 1990 levels by 2040. It’s not maladaptation to make liberal use of air conditioning on a cleaner grid; it’s just necessary.

Critics will often counter that air conditioners don’t destroy heat; they move it, pumping it out of the building and into the street. You cool the inside and warm the outside – and pack enough units into a dense city like Paris, and the effect compounds. As Hans-Martin Füssel of the European Environment Agency told the CBC, dense-city air conditioning “can create an even stronger urban heat island effect”, thanks to the trapped warmth that already makes cities hotter on average than the surrounding countryside.

But the answer isn’t to leave people sweating in darkened 95°F bedrooms; it’s using more efficient units that vent less waste heat. The worst AC option is the one Europeans are too often left with: the wheezing single-hose portable, wedged into a window, which creates a vacuum that sucks hot air back in through every crack even as it labours to cool indoor spaces. Yet, when a more efficient fixed unit requires a landlord’s permission, a costly renovation, or a Genevan doctor’s note, this worst version of the machine becomes the easiest option. Done right, cooling and a livable city aren’t in conflict — but “done right” is precisely what Europe’s rules often make so difficult.

Cooling shouldn’t be political

If Europe’s failure is treating air conditioning as a sin, America’s is treating it as a birthright — cooling without thought, everywhere, all the time. Think of the office tower kept so cold that workers bring sweaters in the summer, or the grocery store with its doors propped open onto the city street, haemorrhaging cold air.

With a major heat dome bearing down on the eastern half of the country this week, PJM, the largest grid operator in North America, is forecasting a possible all-time record of more than 166,000 megawatts of demand, driven largely by air conditioning. The utility is warning that blackouts grow more likely as the system strains. But the problem here isn’t a moral failing; it’s an engineering one. It’s best solved with planning and investment, not with shame. It requires an approach, in fact, like Europe’s, which is already planning for the surge in electricity demand from the electric cars and heat pumps it actually wants.

The point is not that Europe should cool itself the way America does. A normal technology is one you use well, one that is simply deployed where it does the most good. Used well, air conditioning is targeted before it is universal — installed first in the care homes and hospital wards and top-floor apartments where heat actually kills, running on efficient units drawing from a clean grid and paired with the shutters and shade trees and white roofs that Europe is right to love. Add one more thing: the heat pump, which is nothing more than an air conditioner that runs in both directions, cooling in summer and heating in winter, and more efficiently than the boiler it replaces. The same machine, pointed one way, is climate virtue; pointed the other, it is supposedly climate vice. But the distinction was never real.

There’s evidence that this most recent heat wave has finally begun breaking down entrenched European opposition to air conditioning, and Asian makers of ACs are enjoying a boom in European sales. But, at the same time, there’s a risk that the culture war over air conditioning is shifting from across the Atlantic to within Europe itself. In France, the loudest champion of cooling is now the far right’s Marine Le Pen, who has made air conditioning a campaign issue, promising a “grand plan” for it while accusing the left of letting people die for green pieties. The hard left, predictably, has dug in on the other side. And so, a common window unit becomes one more thing to be for or against, depending on your team — a marker of identity rather than a machine that moves heat around.

That is precisely the trap. The whole value of seeing air conditioning as a normal technology is that it lets you ask boring, useful questions — what it costs, whom it saves, and how to run it cleanly — instead of the tribal ones about whose side it’s on. A technology that becomes a symbol isn’t rationally evaluated; it’s embraced or condemned, which is how Europe ended up rationing the most effective heat-protection machine ever invented in the first place. If cooling is recoded as right-wing, the same mistake will just run in reverse, with the people who care most about the climate given one more reason to treat a life-saving thing as suspect.

Heat doesn’t recognise politics. The grandmother broiling on the top floor in Paris, the dazed schoolchild in a classroom with no relief, and the harried nurse on a ward where machines fail in the heat – they don’t need air conditioning to have value. They need it to be normal.