Heatwaves: Overheated homes increase the risk of death at home

In Carpentras, in the Vaucluse region, general practitioner Sébastien Adnot is making a series of visits to overheated apartments. During the summer heatwaves, he cared for Josette, a woman almost 100 years old who gradually weakened despite the presence of her family, IV fluids, and various treatments.

"If I remember correctly, it was between 30 and 32 degrees at her place. Her social housing is poorly insulated, not equipped with air conditioning, she only had a fan," explains Sébastien Adnot, also deputy general secretary of the MG France union.

The doctor believes his patient died of heat-related causes and that she would likely have survived had she been placed in a nursing home or an air-conditioned apartment. This assessment is based on his medical observation of the case and does not constitute a general attribution of these causes to all deaths occurring during heat waves.

Excess mortality at home is still difficult to attribute

During the historic heatwave at the end of June, marked by temperatures exceeding 40°C, all-cause mortality at home was more than twice that observed during comparable periods of the two previous years, according to Public Health France.

The health agency has provisionally recorded 7.300 excess deaths during the heat waves that occurred between the end of May and July 22. This figure is subject to revision, and not all of these deaths can yet be definitively attributed to the heat.

“People are dying at home because their housing did not protect them,” warns Maider Olivier, climate advocacy officer at the Foundation for Housing for the Disadvantaged.

The foundation is asking the State to better take into account the "boiler rooms" and the overexposure of working-class neighborhoods to extreme heat.

Top floor, no shutters and poor insulation

The most difficult dwellings to cool are often small, located on the top floor, not through-units, lacking external sun protection and situated in the heart of urban heat islands.

During the 2003 heatwave, which caused approximately 15.000 deaths in France, mortality at home doubled. Public Health France observed at the time that the risk of death was 4,8 times higher among occupants of older, uninsulated buildings than among those living in newer or insulated buildings.

The risk was also multiplied by 4,1 when the room was located under the roof and by 1,8 for people residing in an urban heat island.

In northeastern Paris, François Raymond, a self-employed nurse, reports that some residents of buildings constructed in the 1960s and 1970s found the June heatwave more bearable than that of 2003. They attribute this improvement to insulation work carried out in recent years.

Deaths in homes lacking sun protection

In Sceaux, in the Hauts-de-Seine department, 93-year-old Louisette Rivalain died at the end of June from hyperthermia after being found unresponsive in her home. Her neighbors are particularly concerned about the absence of shutters, which were temporarily removed by the social housing provider to carry out renovations.

Around the same time, 60-year-old Daniel Topic died in Vannes in an uninsulated, top-floor attic apartment without shutters. A temperature of 45°C was recorded there, according to his brother, interviewed by Ouest-France.

The National Academy of Medicine also notes that 41% of people who died in Paris in August 2003 lived in a one-room dwelling. In 12% of cases, its surface area did not exceed 10 m².

Precarious living conditions increase exposure to heat

Ghislaine Sicre, president of the Convergence infirmière union, also reports worrying situations in small, poorly insulated dwellings, including bungalow-type houses or old fishermen's huts that were not designed to be occupied all year round.

Studies on the 2003 heatwave also highlight the role of medical history, pre-existing conditions, and lack of support. According to François Raymond, "it is social isolation that kills."

“Elderly patients with multiple health conditions who can afford air conditioning in their homes do not go to the hospital. The heatwave will affect those who cannot afford to protect themselves from it; there is a real inequality,” observes Sébastien Adnot.