Europe has been hit by several climate change-fueled heatwaves this summer, estimated to have killed more than 10,000 people in June 2026 alone. That number will surely climb as the extreme heat continues and new mortality numbers come in. But the subject that drew the most media attention wasn’t early warning systems, cooling centers, or protections for outdoor workers. It was air conditioning.
Nearly every interview I did on European heatwaves this summer had the same question: should Europe adopt air conditioning like the United States? My first answer is that, as a planner, I think the people and their policymakers across Europe living through the heatwaves are the ones who should decide how they cool themselves.
But I also think the question is framed wrong. It assumes indoor cooling is something a country can easily decide to either adopt or not, and it assumes the American standard for indoor cooling should be the goal. Roughly 90% of American households have air conditioning, the highest rate in the world, compared to about 27% globally and about 20% across Europe. The United States is the outlier, not the standard. And extreme heat is still our #1 weather-related killer, despite our high air conditioning adoption rates.
Why Europe has hesitated on AC
The debate over the role of air conditioning in Europe has received a lot of coverage. The hesitation to simply adopt it carte blanche isn’t irrational, though; there are real constraints behind it.
The first is that much of the European building stock is very well designed for its historic climate. Europe’s housing is older, with a whole host of regional adaptations that allowed buildings to work for their inhabitants well pre-air conditioning. The older building stock also often predates modern ductwork, and retrofits can be prohibitively expensive.
The second is emissions targets. European countries have mandated greenhouse gas cuts, and adding millions of air conditioning units runs against those commitments. All of those new air conditioners would also dump additional waste heat into their surroundings, increasing the urban heat island effect.
The third is local practices and beliefs, which have to be taken as seriously as the buildings themselves. Opening windows at night to flush the day’s heat is a deeply ingrained method in many places, as are ideas about how air conditioning harms health.
It’s not like Europe has ignored extreme heat as a threat. One of the earliest examples of a heat plan is France’s National Heatwave Plan, implemented after the catastrophic 2003 heatwave that killed 14,802. The national plan focused on improving public health surveillance, early heat warnings, and local emergency responses and is attributed to saving more than 4,000 lives during a heatwave in 2006, all without increases in air conditioning. More recently, European cities have adopted heat action plans (HAPs) and implemented both heat mitigation strategies to reduce the urban heat island and heat management strategies to prepare for and respond to heat that can’t be prevented.
What Europe can learn from the United States
Here’s the lesson United States air conditioner adoption rates actually teach, and it isn’t the one Americans usually offer. Widespread air conditioning doesn’t protect everyone from extreme heat.
Air conditioning protects people who can afford to run it. Energy costs are rising, and many households respond by rationing cooling, setting thermostats higher than is safe to prevent losing service to shutoffs. A tragic share of indoor heat deaths in Arizona occur in homes that have air conditioning but where the unit isn’t working or isn’t being operated for cost concerns.
Air conditioning protects people only while the power holds. A house designed entirely on the assumption of mechanical cooling can become an oven within hours of an energy grid failure, and grids can fail during heatwaves, when demand peaks.
So the United States’ lesson for Europe isn’t simply “install units.” It’s that our high adoption rate measures equipment, not necessarily protection, and a country can reach 90% and still not protect everyone. Those who can install air conditioning in Europe and across the world will increasingly do so, so let’s make sure we don’t leave behind those who cannot.
What the United States can learn from Europe
The exchange runs the other way too. Europe’s older buildings utilize passive cooling strategies we have designed out of ours in the United States: thermal mass, external shutters and shading, cross ventilation, building orientation, tall ceilings, and courtyards. These passive design strategies work with the local climate instead of against it, and keep working even when the grid doesn’t.
The problem raising the air conditioning question is that the passive design strategies no longer match the climate Europe is now experiencing, and are likely not enough on their own to keep buildings thermally safe anymore.
In the United States, our building codes assume mechanical cooling will always be available, which is now one of our weaker links in heat resilience. Passive design, just like air conditioning, isn’t a silver bullet. I certainly wouldn’t survive a Tucson summer in a building with only passive design and no AC.
Practically speaking, though, there are real benefits. Passive design reduces how much mechanical cooling a building needs and makes buildings more resilient when energy grids fail. And the co-benefits of the energy efficiency gained are reducing greenhouse gas emissions that cause climate change and reducing the waste heat that increases the urban heat island effect.
Retrofit buildings, but cool the public ones first
The United States and Europe actually share two challenges. The first is that retrofitting the built environment, for either air conditioning or passive design, is slow and expensive. The second is that both are struggling with treating public cooling as infrastructure. Neither continent has a plan, funding mechanism, or problem owner for doing both at the speed and scale that extreme heat requires.
What’s the solution?
First, retrofit the built environment for the climate we’re now experiencing and will face in the near future. In both the United States and Europe, there is no one-size-fits-all prescription to retrofit buildings and cities. Regional climate, geographic, cultural, and building differences require local approaches that accommodate more indoor cooling and passive design.
Second, treat public cooling as a serious infrastructure investment rather than an emergency response tactic to be activated during heatwaves. This means cooling government buildings, libraries, schools, clinics, community centers, transit stations, trains, and buses. Public cooling scales faster than retrofitting millions of housing units, and spreads the cost instead of leaving it all to individuals.
If you’ve worked on either side of this, in a European city weighing air conditioning or an American one weighing its building code, I’d like to hear what you’re seeing.
— Ladd
In greater Vancouver, where a lot of people live in apartments and condos, we have a patchwork of policies in play. Any new build in BC must now have at least one room in each dwelling unit that can be maintained at <26C. Similar has been proposed for the national building code. A couple of BC municipalities have adopted bylaws requiring landlords to provide the same for tenants, and similar is being considered across the country. One thing about transitioning to a safer built environment for the summer months is that it's going to take a long time and happen via a lot of different pathways. One thing I would love to see is more thoughtful design of underground spaces for emergency circumstances. Many of the buildings have parking 1-4 levels of underground parking, and if power goes out these would be safe spaces. They could be designed more intentionally to support emergency sheltering, when necessary. I feel the same about outdoor spaces, which are generally a safe temperature overnight in this region. How can we plan to adapt these for apartment dwellers when the power goes out?