Operational Optimisation Versus Mechanical Retrofit in Non-Domestic Buildings: An SRI-Informed Life Cycle Assessment

• Integrates Smart Readiness Indicator into scenario-based life cycle assessment. • Compares baseline, heat pump retrofit, and optimised operational control strategies. • optimised operational control reduces energy demand and pollutant impacts without extra embodied emissions. • Low SRI buildings can maintain comfort through operational optimisation. • Proposes a performance-based framework for retrofit decision-making. This study proposes a performance-based framework for building retrofit assessment by integrating the Smart Readiness Indicator (SRI) within a scenario-based Life Cycle Assessment (LCA). Using empirical indoor environmental monitoring data and EnergyPlus simulations, three operational strategies were evaluated for a UK non-domestic social space: a conventional baseline, a mechanical retrofit with an Air Source Heat Pump (ASHP), and an operational optimisation scenario based on adjusted heating and cooling setpoints and schedules. Results show that the operational optimisation scenario achieved lower Cumulative Energy Demand (CED) and Particulate Matter Formation (PMF) than the mechanical retrofit, while exhibiting a slightly higher Global Warming Potential (GWP) due to continued natural gas use. Despite a low SRI classification (Class F), indoor thermal comfort and air quality remained within acceptable thresholds across all scenarios. These findings indicate that operational optimisation can be competitive with mechanical retrofit for selected impact categories under the stated boundary conditions. The study demonstrates how SRI-informed operational assumptions can be embedded within an ISO 14040/44-compliant LCA framework to support evidence-based, performance-driven retrofit decision-making.