This literature review was initiated by the Technical Museum Storage Survey in Swedish museums that the National Council for Cultural Affairs commissioned the Conservation Institute (RIK) of the Central Board of National Antiquities to carry out. The results from the inventory indicate that the relatively narrow limits given in the international preservation literature for relative humidity levels and their variations are not followed by Swedish conservators and curators. Whether this is due to a lack of resources, different priorities or lack of awareness is not clear. It is clear, however, that a large part of Sweden's cultural heritage, in the form of museum exhibits of organic material, are kept in climates that do not conform to international recommendations. The aim of the review is to check if the international ideas on the best climate for the preservation of museum exhibits and artefacts have a scientific basis. Much of the literature refers to organic material. During the literature search and while evaluating scientific reports, I received valuable help from RIK's conservators. My task for RIK - to act as an expert in climate matters during the above-mentioned Technical Museum Storage Room Survey, has provided valuable opportunities to discuss the associated problems with the country's conservators and keepers.