Building-envelope perception, year-round thermal vulnerability, and age-friendly housing for low-income older adults in Daejeon, South Korea

Climate change and population aging are broadening energy poverty from winter heating toward summer overheating, yet South Korean research and policy remain centered on cold homes, leaving the summer side undocumented for low-income older residents of aging low-rise housing. This study asks whether residents’ perception of their building envelope is associated with thermal vulnerability in both seasons, whether that association differs between seasons, and whether any summer association persists once cooling equipment and income are taken into account. A 2024 cross-sectional survey of 128 low-income older households in Seo-gu, Daejeon, provided the data. Perceived envelope condition was measured with an attribute-based index of five window-condition items covering draught, condensation, cracking, warping, and operability (Cronbach’s alpha = 0.93), chosen because it does not restate the thermal outcomes. Cooling was overwhelmingly fan-based: 92.2% used fans and only 33.6% owned an air conditioner. Worse perceived envelope condition was associated with cold and heat experiences and with heating and cooling inadequacy, comparably across seasons, and the summer associations persisted after adjustment for air-conditioner ownership and income. An exploratory typology identified a multiply-vulnerable group (46%) reporting almost no retrofit support. The findings are associational and support envelope-centered, better-targeted energy-welfare policy.