Hygrothermal Performance Analysis of Unheated Zones in a Hımış 20th Century Heritage Dwelling

This study investigates the hygrothermal performance of external wall insulation as part of the retrofit strategies included in four retrofit packages, examined on a traditional hımış house located in the cold climatic context of Güdül, Türkiye. Using WUFI Plus simulations validated by on-site monitoring, the research evaluates multiple retrofit scenarios in a heritage dwelling with a limited heated floor area. Results indicate that applying external wall insulation concurrently on both masonry and timber-framed zones amplifies moisture risks in unheated areas, particularly with masonry walls of low vapour permeability. In contrast, insulating only the timber-framed upper floors proved more effective, improving thermal comfort without elevating relative humidity levels. The findings underscore the importance of fabric-specific, moisture-sensitive retrofit approaches in hybrid structures.