Evaluating retrofit solutions for enhanced energy efficiency in container homes across European climates

This study evaluates retrofit strategies to improve the energy efficiency of container homes across European climates using a life cycle assessment (LCA) approach. The analysis considers the embodied energy of wall insulation materials to determine Energy Payback (EP) and Carbon Payback (CP) periods. Starting from a repurposed shipping container used as a residence, baseline operational energy demand was estimated, and dynamic simulations were performed for three standardised envelope configurations insulated with polyurethane, rock wool, and resin-bonded fibre board. Climatic data from 22 European locations supported the assessment. Results indicate that EP ranges from 13 to 35 years, with shorter paybacks in colder climates (e.g. Warsaw and Krakow), where EP strongly correlates with Heating Degree Days (R2 = 0.95), and longer ones in warmer cities with higher cooling demand (e.g. Athens and Istanbul). CP analysis shows a strong influence of production location: insulation manufactured in China exhibits the highest carbon impact, with rock wool exceeding 80 years of payback due to the carbon-intensive energy mix. The findings highlight the need for context-specific retrofit solutions and demonstrate how material production location significantly affects both environmental performance and overall energy efficiency.