Overheating schools unsuitable for heatwaves

With 12 million students and more than 61.000 establishments, schools are at the heart of the challenges of adapting to climate change.

According to Guillaume Perrin, director of the local government energy renovation program (ACTEE), the need for renovation is massive, but elected officials are facing both a "psychological barrier" and an "investment barrier."

Question. Why are schools so poorly adapted to heat?

Reply. Around 70% of schools were built after the war, between 1950 and 1970. Construction was carried out quickly, fairly uniformly, and not necessarily with the best materials or the best energy performance.

However, given the current trajectory of climate change, we could see the same heat peaks in Brest in 2100 as we see in Perpignan today. Heatwave episodes are no longer restricted to the heart of summer but extend from May to October.

Q. How does this inadequacy manifest itself?

R. In June, the "Racine" action research program was launched, and fifteen schools representative of French territory were equipped with temperature, humidity and CO2 sensors.

The observation is a little frightening in the sense that no school is adapted to the current heatwave.

Temperatures above 30°C were commonly recorded in classrooms, even outside of official heatwave periods, and a record high of 37°C was measured in one school.

Even very recent schools, built after 2019, are already experiencing significant overheating problems linked to their design, namely large, unprotected bay windows and excessive insulation without solar protection which generates a "thermos" effect.

Q. Nearly 1.900 schools, both public and private, have been closed out of around 48.000. Does that seem like a small number?

R. The mayors' priority is, above all, childcare, even if it means having shorter workdays. This number of closures doesn't only reflect schools that are problematic, as this decision is often made as a last resort, since parents also need to find childcare.

As there is no defined maximum temperature criterion, decisions are made on a case-by-case basis.

Q. What are the obstacles encountered in renovating schools?

R. Until now, we tended to focus on winter comfort. Today, with climate change, we realize that summer comfort will become the major issue in building design.

If we really want to act on the building, the priority is the insulation of the roof and walls to ensure good thermal inertia of the building.

Among the obstacles, there is first of all a societal issue with the fact of saying to ourselves, for elected officials, that we have entered the era of climate change, that heat waves will be much more frequent than before and that it is not enough just to wait a week in the shade and say that it will pass.

The second issue is that of resources. An elected official will be caught between different demands from his constituents, whether to remove potholes in the street or renovate essential public buildings.

In the second case, it will very quickly face a fairly significant investment wall. The "green fund" launched by the government in 2023, for example, has been reduced from 2,5 billion to 1,15 billion this year, while the energy savings certificate (CEE) system is quite complex to implement.

Q. In 2023, Emmanuel Macron launched a plan to renovate 40.000 schools by 2034. Where are we now?

R. Around 5.000 schools have been renovated, and it's working quite well because there's engineering support. The other difficulty is that a mayor's term lasts six years, including four and a half years of actual action. However, renovating one's heritage isn't feasible in such a short time, especially since without support, it's difficult to navigate. There are a multitude of funds, with many acronyms and many different specifications.