Life in urban areas is already barely bearable during such periods, and it will only get worse. The bottom line is that Europe, along with other advanced economies, will have to adapt to this structural shift.

From American Luxury to European Necessity

One of the most visible examples of this adaptation is air conditioning. Roughly 90% of American households are already equipped with it, compared with only around one-fifth in Europe.

The technology is even more widespread in Japan, the world leader in this regard, while China is catching up fast. Rising living standards, urbanization and increasingly frequent heat waves are driving a sharp increase in the number of air-conditioned Chinese households.

Europe, by contrast, remains far behind, though this considerable gap should narrow gradually as hot summers become more frequent.

Long dismissed on the Old Continent as an unnecessary luxury, and something of an American quirk, air conditioning is fast becoming a standard feature of homes, offices, hospitals and schools.

Demand, however, is not rising from households alone. Office buildings, industrial facilities and, above all, data centers are also driving the need for more cooling capacity.

As a result, air conditioning manufacturers now find themselves at the profitable crossroads of two powerful long-term trends: global warming and the rapid expansion of digital infrastructure.

Politics Complicates the Picture

As with any investment, there is no such thing as a sure bet, and every opportunity carries its own risks. In Europe, politicians and regulators, in particular, present an unsurprising complication to what might otherwise look like a straightforward wager.

France illustrates the point well. Heat waves there have pushed even some in the environmentalist camp to reconsider their previous stance. The leader of the French Greens, Marine Tondelier, has acknowledged that there are places where air conditioning can no longer be avoided, while also cautioning that installing it in poorly insulated buildings makes little sense.

On hospitals and nursing homes, there is now relatively broad consensus, given that extreme heat can directly endanger human health and lives. The debate is more complex when it comes to schools and households. Marine Le Pen is pushing for a large-scale plan to equip public buildings with air conditioning, while Environment Minister Monique Barbut has warned against the idea that it is enough to “put air conditioning everywhere”.

Physical and regulatory restrictions also come into play. France has a large number of historic districts where mounting an outdoor unit on a building's facade is simply not permitted. The installation process is shaped by heritage authorities, objections from neighbors and strict noise regulations, meaning that obtaining a permit can be a lengthy affair.

One important argument in favor of air conditioning, however, is that France has a large supply of low-emission electricity. Air conditioning also boosts electricity consumption on sunny summer days, precisely when solar output is at its peak. This does not fully resolve the problem of electricity surpluses, but it does allow France to put part of that excess production to good use, at exactly the moment when there is most of it on the grid.

Riding the Data Center Boom

Resistance to air conditioning is thus increasingly reminiscent of tilting at windmills, at least in the long run. This raises the fundamental question of how investors can actually profit from the trend.

The picture is complicated somewhat by the fact that air conditioning and cooling systems are an integral part of the new data centers springing up on a massive scale to serve artificial intelligence (AI). Since 2025, a large share of suppliers of technology and construction solutions for data centers have seen a veritable explosion in both orders and stock market valuations, and manufacturers of cooling systems are no exception.

The clearest example is the American company Comfort Systems USA, whose share price has more than doubled since the start of this year. The company installs air conditioning, ductwork and other technical systems, and an increasingly large share of its growth now stems specifically from data center construction.

Shares in AAON, which makes commercial air conditioning and liquid cooling systems, have risen by approximately 70%. In both cases, however, this growth has little to do with European households buying air conditioners. Cloud storage and artificial intelligence remain the main drivers.

This, of course, entails risk as well. Should investors one day begin to doubt the valuations of AI-related companies, or should the big technology firms slow their expansion, a stock market sell-off would also hit cooling suppliers, even though long-term demand for their technologies would remain high. When sentiment turns sharply, the whole narrative tends to be sold off at once.

The Slow and Steady Alternative

Not every air conditioning stock depends on the AI boom, however. A second group of manufacturers relies far more on ordinary demand from households and businesses, led by names such as Carrier Global, Daikin Industries, Midea and Gree Electric.

Carrier, which draws a large share of its revenue from residential air conditioners, has seen its market value rise by about one-third since the start of the year. Japan's Daikin has gained about 17%, and its European revenue from air conditioning and refrigeration equipment climbed nearly 10% over the last fiscal year. A weaker Japanese yen is also flattering Daikin's results, since it raises the value of foreign sales and profits once converted back into yen.

These stocks, too, have long since emerged from obscurity. Even so, they do not carry the same stretched valuations as companies directly tied to data center construction. Investors here are not betting on the artificial intelligence craze lasting another year, but on a slower, more stable structural shift.

Put simply, air conditioning in Europe is moving from luxury to necessity, and it is precisely this kind of transformation that tends to be most lucrative in capital markets, particularly when it is already clearly visible but has not yet been fully priced in.