The health effects of housing conditions (materials, ventilation, luminosity, space distribution, etc.) are well known to specialists, but what do residents think? We propose to show how health literacy in the home (HLH), i.e. the ability of residents to relate their physiological conditions to their living conditions, is a factor in explaining social inequalities in health. Levels of LSH are linked to situations of “residential stress”, i.e. difficulties in mastering the environment, taking up residence and drawing resources from the habitat. To clarify these propositions, we intend first to explain the pedagogical methodology of the SAPHIR (Santé Paris Habitat Histoire Immeuble Résidentiel) research-action program, supported by the Agence Régionale de Santé Ile de France. This is a qualitative survey of 12 popular housing buildings in the Ile-de-France region, built at different dates, with different levels of thermal and acoustic comfort. This survey, based on areas marked by social inequalities in health, alternates between educational cafés, focus groups, non-directive interviews and inhabited surveys.