Comparative Evaluation of Retrofit Strategies for Enhancing the Sustainability Existing Building

Purpose: This study aims to analyze retrofit strategies for enhancing the sustainable use of nationally registered cultural heritage buildings. It focuses on improving energy performance and managing moisture risks to ensure the longevity and usability of these historic structures. Method: On-site measurements and building performance simulations were conducted for the G Medical Museum. Parameters such as thermal transmittance, solar heat gain coefficient (SHGC), and air leakage rates were assessed. Additionally, hygrothermal simulations using WUFI were carried out to evaluate the risk of moisture accumulation and mold formation. Various retrofit scenarios, including airtightness enhancement, wall insulation, and window upgrades, were analyzed for their energy efficiency and moisture control effectiveness. Result: The initial evaluation revealed substandard performance: thermal transmittance values of 1.94W/m2 K and 4.30W/m2 K, SHGC of 0.70, and severe air leakage of 63 ACH. WUFI simulations indicated a high risk of condensation and mold. Among the proposed retrofit strategies, the D scenario —combining airtightness improvement, insulation, and window upgrades—achieved the best results, reducing energy consumption by 45.4%. However, increased cooling demand highlighted the need for additional shading and ventilation strategies. These findings underscore the necessity of an integrated approach combining energy efficiency and moisture management in retrofitting cultural heritage buildings.