Overheating Risk Assessment in Insulation-Based Energy Renovations in Spain

This study examines the impact of thermal insulation-based renovations on the overheating risk in residential buildings across different climatic conditions in Spain. While the European Union (EU) regulations aim to improve energy efficiency in buildings, increasing thermal insulation can lead to significant energy savings, especially in areas with high heating demand. However, excessive insulation may raise indoor temperatures, increasing the risk of overheating. The research focuses on a typical multi-family residential building from the 1960s and 1970s, initially lacking insulation, and analyses various renovation strategies in different climatic conditions in Spain. The study evaluates four types of passive renovations—facade exterior insulation, roof insulation, window replacement, and their combination – at three efficiency levels – basic, national building code (NBC) required, and EnerPHit standard. A three-stage methodology is employed: identifying archetypes and renovation strategies, conducting a Building Performance Simulation (BPS), and assessing overheating hours based on the CIBSE thermal comfort model. Results reveal that climatic conditions significantly influence overheating risks, identifying critical zones in Spain where overheating may be a concern. The findings suggest that these areas require more targeted solutions to prevent overheating while improving energy efficiency through renovations.