###### Abstract  
Energy retrofits can enhance the liveability and efficiency of historic buildings while preserving their historic and aesthetic values. However, measures like improved insulation and airtightness may increase their vulnerability to overheating and climate change may further worsen their performance in the future. This paper investigates indoor overheating risks brought by climate change in retrofitted historic buildings and proposes effective adaptation strategies. Firstly, local weather conditions are analysed to identify homogenous climatic zones. For each climatic zone, \"a business-as-usual\" emissions scenario is adopted, and most representative regional climate models are selected to obtain hourly output of future climate projection. A comparative study is adopted where typical alpine residential buildings, \"Portici house\", are simulated with regard to future energy use and indoor thermal state using the dynamic model in EnergyPlus. Energy use and indoor thermal conditions are compared before and after energy retrofit, as well as under present and future climate conditions. The results demonstrate that retrofit interventions could significantly improve energy efficiency of historic buildings in both present and future scenarios. A change in climate together with retrofit interventions will, however, result in higher risk of indoor overheating in South Tyrol. Potential negative side effects of energy retrofit could be controlled by adopting adequate shading and ventilation approaches that minimise, or eliminate, the risk of overheating during high temperature periods while optimising historic buildings' energy performance. b 2022 20220111 July 202211 July 202215 July 20222011 July 20222011 July 202211 July  
many alpine regions already suffers a more severe temperature increase compared to other regions in Europe. The 2018 South Tyrolean Climate Report [5] indicated that the average summer temperature has risen 2.2 \({}^{\circ}\)C from the 1960s and that it will further increase up to 5 \({}^{\circ}\)C under the most pessimistic scenario by 2100. Along with the temperature rise, days with extreme temperature will be more frequent. For instance, the number of summer days (days during which the maximum temperature is above 20 \({}^{\circ}\)C) in the capital of South Tyrol has grown from around 100 in the 1960s to around 115 in 2018, and it will reach to 175 by 2100. Similarly, the number of days when the minimum temperature remains above 20 \({}^{\circ}\)C rises significantly. The previous highest record of South Tyrol was 24 days in 2015, while there would be an average of more than 60 days a year by 2100. Changes in the climate may influence the patterns of energy use, thermal comfort, and hydrothermal performance of historic buildings. The current studies mainly focus on the challenges that the climate will impose on the preservation of artifacts inside historic buildings [6; 7; 8], while the thermal comfort is a growing issue. Apparent temperature rises in the microclimate will be identified in the historic city centre in the future [9], which will be a serious threat to socio-culture life. Moreover, thermal comfort stress inside historic buildings is also an essential cause of healthy and productivity problems. Since most historic buildings are not equipped with modern cooling systems and work in \"free-running\" mode in the summer, the combination of thermal mass and natural ventilation is commonly used as a passive cooling strategy. The effectiveness of this passive cooling is dependent on buildings' thermal mass; user behaviour; and climate factors such as outdoor temperature daily swing, solar radiation, etc. [10; 11]. With outside temperature and humidity changing in the future, the passive cooling strategy may soon fail to ensure comfortable thermal conditions [12]. Comfort and environmental issues can also be found in the winter.