Configuration over Transition Temperature: A Climate-Adaptive Strategy for Sustainable Office Building Energy Efficiency with Thermochromic Glazing

Buildings account for a substantial share of global energy use and carbon emissions, making climate-adaptive building envelopes critical for sustainable urban development. Thermochromic glazing dynamically modulates solar transmittance with temperature, offering a promising pathway toward sustainable buildings; however, guidance on transition temperatures and composite configurations across China’s five climate zones remains limited. This study therefore derives an evidence-based, climate-adaptive design strategy for thermochromic hydrogel-based insulating glass units in office buildings across these climate zones. To achieve this aim, an EnergyPlus model validated against summer field measurements in Chongqing quantified heating and cooling loads for 220 simulated cases and identified suitable glazing configurations and transition temperature, while RF-SHAP ranked factor importance. The results provide climate- and orientation-specific guidance for office-glazing selection: a 25 °C transition temperature delivers 2.76–4.04% total load savings in the two warm zones, and surface-2/3 Low-E composite TSG achieves up to 12.93%. In cold and severe cold zones, south-facing use can raise loads, whereas west-, east-, and north-facing applications retain saving potential; in temperate climates, single-silver Low-E glass is generally preferable. The RF-SHAP analysis ranks the factors influencing the total energy saving rate as glazing configuration > climate zone > orientation > transition temperature. These findings translate into a practical climate zone-based selection framework that supports sustainable building envelope design and retrofitting, helping to reduce operational energy consumption and carbon emissions while maintaining indoor thermal comfort.