Designing Sustainable Residential Environments for Aging-in-Place: Conceptual Integration and Operationalization Through the EREEM Matrix

Population aging is driving increasing demand for residential environments that support safety, independence, and well-being for older adults. However, existing design guidelines remain fragmented and lack measurable spatial indicators for architectural evaluation. This study proposes the Elderly Residential Environment Evaluation Matrix (EREEM), an integrated framework that translates interdisciplinary design principles into operational spatial indicators across six core dimensions: safety, accessibility, autonomy, privacy, social interaction, and adaptability. An expert survey with 36 specialists evaluated 54 initial indicators (Cronbach’s α = 0.978), which were subsequently screened based on expert-rated importance, conceptual overlap, and field observability, resulting in a 24-indicator operational set for exploratory field assessment in four residential environments in Vietnam. The results indicate that safety and accessibility form foundational conditions, while higher-level principles depend on spatial organization. The study contributes a systematic evaluation tool and provides a practical basis for age-friendly and socially sustainable residential design.