Museums are often housed in monumental buildings. These buildings were originally not built for this purpose. For the preservation of the artefacts in a museum the indoor climate is often restricted to a very narrow interval for temperature, but most of all for relative humidity. This restricted indoor climate originally dates from the 1970-ties. This indoor climate, however, does not fit well into an old building. The indoor surface conditions near cold walls under winter conditions lead to mould building and other deterioration of the wall surfaces. But principally the museum conditions of artefacts near the cold walls are not in line with museum recommendations. For some typical Dutch museums case studies have been done to show the build...