The thesis investigates the hygrothermal performance of exterior walls constructed with cast-in-place concrete in permanent EPS formwork (ICF walls), based on three Swedish climate zones. The purpose was to analyze how different configurations of this wall system affect moisture management and thermal insulation, as well as to identify optimal designs for energy-efficient and sustainable construction. Hygrothermal simulations were conducted in the software WUFI Pro for twelve wall types across the climate zones of Lund, Stockholm, and Kiruna. The main parameters examined were U-value, relative humidity, moisture content, and desorption capacity.

The results show that a balanced distribution of insulation and the use of more vapor-open façade materials, such as wood cladding, provide the best hygrothermal properties. Walls with 200 mm of EPS insulation on both the interior and exterior sides, combined with a wood cladding façade, demonstrated particularly high levels of hygrothermal performance.

The conclusion is that, under the right conditions, ICF walls can offer high performance and long-term durability in Swedish climate conditions. Further research is suggested on how user behavior and installations affect moisture load.