“Urgent: due to extreme weather conditions, the air conditioning system on floors one to seven has been forced to shut down for the rest of the day.” That was the message they received. workers of the Berlaymont building, headquarters of the presidency of the community Executive, in the middle of a heat wave. The episode ignited debate in the city. The air conditioning was turned off only on the first seven floors, while the upper offices continued to have air conditioning on a day when the mercury reached 35 degrees. Among the reasons that have been considered, although they have not been clarified, is an overheating of the system.
The debate about air conditioning when heat waves arrive is beginning to be common in Europe. In France, this summer, where temperatures have exceeded 40 degrees, It has almost become a state issue. Marine Le Pen has promised a large air conditioning plan to adapt hospitals, schools and residences. Even the most environmentalist parties have winked at the need to air-condition certain public buildings of special interest, although they insist that installing more devices will not solve the problem of heating.
The mayor of Paris bought 1,200 devices for the capital’s schools, while everywhere In the country, 3,000 schools were closed due to the heat. In addition, trains have been canceled and two nuclear power plants have even been forced to shut down. The debate in this country, known for its aversion to air conditioning, has heated up as its streets have. Only 25% of French people have air conditioning.
In Germany it is also not common to have air conditioning in hospitals and other public buildings, although the debate is also beginning to permeate public opinion. In Leipzig, according to the Huffington Post, the tram lines have to be adapted because several elements of the network have melted.
In Europe, the penetration of air conditioning is lower than in the United States, but even in countries like Spain, where more than 50% of the population has these devices, every year the debate is reopened on issues such as temperatures in schools. With increasingly higher temperatures, will the use of air conditioning skyrocket and, with it, electricity consumption and emissions? And what happens with the heat island effect in cities? Does multiplying the devices increase the temperature in already overheated streets with a shortage of trees? Those who defend air conditioning present it as a tool to guarantee bearable living conditions and remember that, in Europe, a growing part of electricity comes from renewable sources: 47% of the electricity consumed in the Old Continent in 2025 came from this type of energy. Its critics, on the other hand, maintain that it increases electricity consumption, strains networks, expels more hot air outside and does not address the underlying problem: climate change.
Consumption on the rise
According to data from the International Energy Agency (IEA), space cooling, based mainly on air conditioning although it also includes fans, consumed in 2022 about 2,100 terawatt hours (TWh) of electricity, around 7% of global electricity consumption of that year. As some of that electricity still comes from fossil fuels, the IEA estimates that around one billion tonnes of CO₂ were emitted. In addition, it is expected that the global park will triple by 2050. Regarding the outside temperature, various studies estimate that air conditioners can raise it between 0.5 and 2º in certain urban areas.
At this point, two issues must be taken into account. The first is the European Energy Efficiency Directive, which aims for the real estate stock to be zero emissions by 2050, an objective that necessarily involves reducing the energy demand of buildings. Air conditioning represents approximately 50% of their energy consumption. The second is the regulatory transition around fluorinated gases: hydrofluorocarbons (HFC) are progressively disappearing from the European market to make way for refrigerants with lower warming potential. «The main gases that have been used have been R22, R410A and R32. R22 has been banned in the EU since 2015 because it contains chlorine and these compounds have a high environmental impact. It was later replaced by R410A, which does not contain chlorine, but does contain fluorine, so it will also disappear. “Air conditioning is not being prohibited, but rather the use of certain gases,” explains Nazareth Ruiz Marín, from the Department of Thermal Machines and Engines at the University of Cádiz.
How do we acclimatize?
These days there are many media that mention the cooling system it has. Paris. The French capital cools museums, hospitals and schools using the cold water of the Seine thanks to a network of 120 kilometers of pipes which began to be planned in the nineties and which now wants to triple to reach more districts and provide service to hospitals, schools, daycare centers and nursing homes. For Nazareth Ruiz, however, acting at the level of large urban facilities should be the last layer in which to intervene. «The first layer is the building. I give as an example a school with a completely empty courtyard, without trees, awnings or covers; that is, without any sun protection. Buildings must be designed that require almost no cooling and alternatives to air conditioning systems must be prioritized. In schools, for example,or first is to create shadow; then, improve insulation, promote cross ventilation, incorporate more vegetation and use advanced materials, such as phase change materials», explains the researcher, specialized precisely in these systems. «They are materials that absorb heat from the outside and use it to change phase. They then release it gradually, making the temperature between day and night much more stable inside the building. They work especially well in places where there is a difference of about ten degrees between the maximum daytime and nighttime temperatures, something that occurs in many areas of Spain. “They can reduce the interior temperature by up to six degrees.” Once action has been taken on the building, he adds, “you can move on to the equipment (heat pumps or aerothermal) and, finally, to urban-scale solutions.”
Solutions such as ventilated or double facades, taking advantage of the practically constant temperature of the subsoil (between 15 and 20 degrees) to air-condition buildings in both summer and winter, installing awnings and tarps, using evaporative cooling systems or resorting to night ventilation and green roofs and facades can significantly reduce the need for air conditioning and are increasingly common in discourses on rehabilitation and adaptation. «According to the European Commission, heat pumps are usually between three and five times more efficient than a gas boiler. For every kilowatt of electricity consumed, they produce, on average, between three and four thermal kilowatts, both heat and cold,” says Marta San Román, director of the Association of Air Conditioning Equipment Manufacturers (AFEC).
The person in charge also remembers that «Aerothermal energy is a type of heat pump that obtains energy from the air. The other two alternatives are hydrothermal and geothermal. Aerothermal energy can transfer that energy from air to air (what is traditionally known as air conditioning) or from air to water to power radiators, underfloor heating or cooling, fan coil units, which provide both heat and cold, and also to produce domestic hot water,” says Marta San Román.
The refrigerated shirt of the National Team
►Among the many news stories generated by the Soccer World Cup being held these days, there are several that have to do with the heat. For example, the aforementioned mandatory stops in matches or the cooling vests used by the Spanish team. Everything has been said about the t-shirt, including that they are made of ice. The truth is that they are based on so-called phase change materials (PCM). “The operating principle follows the same logic that allows ice to melt by absorbing heat, but in this case the melting point can be programmed to be well above 0 °C. The vest sits over the shirt and its PCM packets cover the torso, abdomen and back. When melted, they provide constant cooling,” explains Nazareth Ruiz. The researcher explains that these PCMs (like coconut oil) are also being tested in buildings.