Two-Stage Retrofit of Rural Houses in Shanghai: Coupling Spatial Reconfiguration and Envelope Enhancement Based on Behaviour–Environment Fit

Older residents of Chinese rural houses spend much of the day in courtyards and on terraces as well as indoors, so an indoor-only comfort assessment can misrepresent their thermal exposure. This study proposes a two-stage, rule-based retrofit framework that evaluates spatial reconfiguration and envelope enhancement under one occupancy weighting: spatial measures are simulated first, and the seasonal deficits they leave determine which envelope measures are selected. The framework was applied to a typical three-storey rural house in Shanghai with a code-compliant reference envelope. Free-running PMV in ten rooms (EnergyPlus) and UTCI in two outdoor spaces (Ladybug) were weighted by the survey-informed occupancy of residents aged 60 and over (85 respondents) into a person–space matching degree M. Baseline M was 19.6% in summer and 40.4% in winter, and excluding the outdoor spaces raised it by 2.3 and 3.5 percentage points. A fixed overhang gained 0.5 points in summer but lost 4.2 points in winter. The full deficit-matched package gave the largest winter improvement (M 51.2%), but two of its measures served rarely used rooms: a leaner package without them retained 91% of the summer and 93% of the winter gain at 62% of the cost. Replacing the fixed overhang with a retractable awning explained 88% of the additional winter gain over a package without diagnosis. A material-only package reached a similar indoor gain at lower cost but left the outdoor spaces unchanged. Static payback periods exceeded 280 years for all packages, so retrofit of this dwelling is justified by comfort rather than energy savings. The results refer to a single case under simulated conditions and assumed room-level occupancy.