To launch its Observatory, Leroy Merlin commissioned Ifop to conduct a major survey on summer comfort, involving 6,042 French citizens representative of the population aged 18 and older. The fieldwork was carried out afterthe first heat wave in May (June 3–17, 2026). The goal was to understand how extreme heat changes people’s relationship with their homes, impacts residents’ daily lives, and reveals new vulnerabilities in the face of climate change.
The results show that housing, long perceived as a refuge, no longer always provides effective protection from the heat. Nearly 19 million French people report having had to temporarily leave their homes due to extreme heat, while 30% believe their homes can become uninhabitable during heat waves.
Another key finding: young adults appear to be the most overlooked group when it comes to summer comfort. While vulnerability to heat is typically associated with the elderly, people in poor health, or young children, 18- to 24-year-olds are among those most affected in their daily lives. 92% report experiencing at least one difficulty in their homes during heat waves, 60% have already had to leave their homes temporarily, and 66% are even considering moving because of the heat.
The study also highlights that summer comfort depends not only on the region where one lives, but very strongly on the characteristics of the home: insulation, floor area, floor level, occupancy status, and the presence of sun protection. Poorly insulated homes appear to be particularly vulnerable: 61% of their residents find them uncomfortable during heat waves, compared to an average of 27%.
Another key finding: heat directly affects sleep, recovery, and health. Nearly one in two French people say it is too hot at night in their homes, and the bedroom becomes the most difficult room to be in during heat waves. Young people, renters, and residents of apartments, small homes, or poorly insulated homes appear to be the most vulnerable groups.
Faced with this situation, the French are already adapting: 90% report having changed at least one habit in their homes, such as closing the shutters during the day or ventilating at night. However, the transition to more sustainable adaptations remains unevenly accessible, hindered by cost, tenant status, or a lack of guidance on which solutions to prioritize.
Beyond a matter of comfort, this study shows that the sustainable homes of tomorrow must not only consume less energy—they must also better protect their residents year-round.