A weighted indoor environmental quality evaluation system for residential satisfaction of older adults in China

Population ageing has intensified demand for age-friendly housing, yet existing indoor environmental quality (IEQ) assessment schemes rely on expert-defined or fixed weights and rarely reflect older occupants’ priorities. From the perspective of person-environment fit in environmental gerontology, this study developed a weighted IEQ evaluation system for the residential satisfaction of older adults. Six indoor environmental factors were examined: ventilation, daylighting, indoor temperature, noise, CO₂ concentration and relative humidity. Data were collected in Zhuzhou, China, including 210 questionnaires (154 from older adults) and 35 semi-structured interviews, with both sources equally weighted. The integrated questionnaire–interview analysis yielded estimated weights of 20.50% for ventilation, 18.95% for daylighting, 17.64% for indoor temperature, 16.67% for noise, 15.19% for CO₂ concentration, and 11.05% for relative humidity. These estimates reflect sampled priorities, and the relative ordering of middle-ranked factors was interpreted as indicative. Combining these weights with elderly-specific thresholds, a four-indicator scoring system (air quality, daylighting, indoor temperature and noise) was applied to an age-friendly recreational building in Zhuzhou through simulation, identifying daylighting and thermal performance as improvement priorities. The study operationalizes person–environment fit at the dwelling scale and provides a user-oriented, context-specific reference for evaluating and prioritizing age-friendly residential retrofits in China.