This paper considers the models that are available to analyse the risk of interstitial condensation within structures. To run the models, certain properties of materials need to be known. The paper discusses the availability of data on these properties and the appropriate boundary conditions that should be used, and makes recommendations on which models should be used for different types of structure. The models specifically discussed and compared are: BRECON (developed by BRE to carry out the calculations for BS 5250), ICOND (under development to carry out calculations to BS EN ISO 13788) and MATCH (a commonly used program that can simulate moisture movement for periods of a year or more at hourly time-steps). 12 pages.