Review paper: Indoor humidity calculation procedures

Recently the results from a number of studies of the absorption and desorption of moisture by building materials have been published. Working independently, various groups have evolved their own theories and experimental methods. Afodelling water vapour conditions in buildings (1) was such a report which gave an account of the progress so far at BRE. This paper sets out the common basic theory, then reviews seven methods including those of BRE, EDF and CSTB of France and IEA Annex 14 of Belgium. What emerges is that all the work is at some interim stage and nobody offers definitive correct answers. The suitability of any particular theory depends on aligning it to the desired accuracy. Also, harmonisation of terminology and nomenclature, if it were possible, would be a tremendous advantage.