Microclimate Control Strategies for the Protection of Historic Buildings: The Case of the Church of San Giacomo in Como

Preserving high-value historic buildings requires a careful balance between occupant thermal comfort, conservation of sensitive materials and overall energy efficiency. In such regards, the study presents a comprehensive thermohygrometric assessment of the Church of San Giacomo in Como, integrating longterm microclimatic monitoring and dynamic state energy modelling to support the definition of conservation and compatible HVAC strategies. A whole-building dynamic simulation model was developed in EnergyPlus to evaluate multiple heating scenarios focused on a low-temperature radiant floor system integrated beneath the existing stone pavement. The comparative analysis of different setpoints (14 °C, 16 °C, 18 °C) demonstrates that continuous operation at 16 °C provides the most favourable balance between indoor stability, energy performance and material conservation risk, mitigating both high humidity in wintertime and excessive dryness associated with higher setpoints. Beyond informing HVAC design choices, the multilevel methodological framework adopted offers a quantitative basis for defining visitor flow management strategies. By characterising the microclimatic sensitivity of the indoor environment to visitor perturbations, the approach enables the formulation of occupancy schedules based on proven data aimed at maintaining the indoor climate within optimal conservation conditions.