Europe is getting hotter, and the continent’s old assumption that most homes can get through summer without mechanical cooling is starting to look less like thrift and more like bad planning.
During a late-June heat wave that sent temperatures above 40 degrees Celsius in parts of Europe, shoppers in France rushed stores for portable fans and air conditioners. The International Energy Agency says global demand for cooling is rising as the climate warms, and projects that two-thirds of households could have an air conditioner by 2050.
The European starting point is low. The IEA says about 20 percent of European households have air conditioning. In the UK, research cited by the Energy Demand Research Centre puts home AC ownership at about 4 percent. In the US, the comparable figure is roughly 90 percent, helped by cheaper electricity.
That gap is becoming political. Marine Le Pen has promised to expand air conditioning in France if her party takes power. Britain’s Conservatives have said they would reverse net-zero rules that limit AC installation in new homes. Critics on the left argue that wider adoption could mostly help wealthier households while increasing power demand and emissions.
The machines solve one problem and worsen another
Cooling is no longer just about comfort. Researchers have linked air conditioning to better sleep, safer classrooms and lower heat-related mortality. One research group estimated in The Lancet that air conditioning prevented nearly 200,000 premature deaths among people over 65 in 2019.
Nicole Miranda, a senior lecturer in engineering and carbon reduction manager at the University of Oxford, has studied how heat exposure and cooling demand could change if global warming reaches 2 degrees Celsius above preindustrial levels. Her team found that countries including the UK, Switzerland, Norway and Finland could see some of the sharpest relative increases.
Miranda says Europe will need more cooling to protect people, with the harder task being how to deliver it efficiently and fairly rather than through a stampede for inefficient portable units.
The engineering problem is blunt. Conventional air conditioners use refrigerants that shift between liquid and gas, pulling heat from indoor air and dumping it outside. The IEA’s Fabian Voswinkel says cooling is expected to become one of the biggest sources of electricity demand growth, alongside data centers. Space-cooling electricity demand could more than triple by 2050.
Refrigerants add another mess. Fluorinated gases can have warming effects thousands of times stronger than carbon dioxide if they escape. The European Union adopted rules in 2024 to phase them down. Voswinkel says air conditioners and heat pumps using those gases will be barred from sale in Europe in the next few years. Replacements have drawbacks too: propane burns easily, and ammonia is toxic.
Solid-state cooling is promising, and still early
Some researchers are trying to remove refrigerants from the loop. Paul Motzki, a professor of smart material systems at Saarland University in Germany, leads an EU-funded consortium working with nickel-titanium. When the material is stretched and released, it returns to shape while absorbing heat, an effect known as elastocaloric cooling.
Motzki says the approach could cool rooms by 5 to 10 degrees Celsius and may beat the efficiency of today’s conventional systems. His team is testing a lab prototype and expects deployment in new buildings within the next few years. The group is working with Irish company Exergyn, which is developing a refrigerant-free heat pump.
Other bets are scattered across the field. Brooklyn-based Mimic Systems is testing a semiconductor-based heat pump in a Vancouver apartment. Magnotherm, spun out of the Technical University of Darmstadt, is using magnetic fields for refrigeration and plans a supermarket test in Germany before moving toward air conditioning. Barocal, a University of Cambridge spinoff, is developing cooling based on flexible plastic crystals compressed in a pressure chamber, and recently raised $10 million in seed funding.
Lindsay Rasmussen of Third Derivative, the climate-tech accelerator founded by the Rocky Mountain Institute, says solid-state cooling remains unproven at scale. She also says capital and industrial partnerships could speed the field up. Large manufacturers such as Daikin and Samsung already dominate cooling and monitor emerging technologies closely.
Miranda and Voswinkel argue that Europe still needs a cooling hierarchy: stop buildings overheating first, using trees, shade, reflective materials and natural ventilation, then add active cooling where it is most needed, including schools, hospitals and care homes. Paris offers one model, according to Voswinkel: before the 2024 Olympics, the city expanded a district network to send chilled river water through underground pipes to cool public buildings.
This story draws on original reporting from Ars Technica.
