This paper deals with unheated basements in existing buildings. Due to soaring
housing prices these rooms may be increasingly used for the storage of sensitive goods and
temporarily for leisure activities. In order to keep these rooms free of mould various technical
solutions are available. However, it is unclear whether they prevent mould growth and how high
their energy demand is. This question is explored by simulating an unheated basement in an
uninsulated, a renovated and a newly built building. The paper considers and evalueates four different operation modes for the basement.
