Läckö Castle in Southern Sweden is located on a small peninsula in Lake Vänern. The origin of the Castle is from medieval times but it present appearance is from the 17th century. It has never been permanently heated and hence it is interesting as a research object in the area of indoor climate and the impact on hygroscopic, organic materials. At the moment, monitoring of temperature, relative humidity and simultaneously the deformation of the painted, wooden wall panels in taken place. This work is a collaboration project between Department of Conservation, University of Gothenburg, Sweden and CNR Ivalsa with in the research project “Spara och bevara” (Energy Efficiency in Historic Buildings).