Beyond air quality concerns, access to decent housing is a fundamental right and a major determinant of health, as recognized by the World Health Organization (WHO). The effects of poor housing quality and overcrowding on mental health, anxiety, depression, and aggression have been scientifically demonstrated. Substandard housing also has a major impact on physical health by facilitating the spread of infectious diseases. The presence of mold poses a health risk, particularly causing irritation and respiratory symptoms, especially for at-risk individuals. There are therefore clear links between people’s health, the quality of their housing, and where they live. According to WHO Europe, there are nearly 130,000 deaths each year associated with inadequate housing conditions in Europe.

Housing is also a major determinant of social and regional health inequalities, which are exacerbated when residents—most often those in disadvantaged social situations—live in substandard housing and environments. Social inequalities in access to housing thus hit younger generations, women, and minorities particularly hard, as they also face significant discrimination in accessing housing. The combination of low incomes, poor housing quality, and high energy costs can also lead to energy poverty. According to the National Observatory on Energy Poverty (ONPE), more than 3 million people are affected. Beyond the impacts of the cold, these situations contribute to the use of portable or makeshift heating devices (such as braziers), as well as the blocking of air inlets and outlets, which leads to the accumulation of indoor air pollutants and high humidity levels. Furthermore, the current context of climate change will also exacerbate the issue of summer comfort and its consequences on residents’ mental and physical health.