Surveys existing studies of natural ventilation which are of two types; full scale studies of small domestic buildings and analogue studies, mainly electronic digital analogues. Gives simple nomograms, deduced from the analogue studies which are useful for estimating gross building infiltration rates underextreme meteorological conditions. States that none of the analogue studies have been carried out in conJunction with simultaneous full scale or model scale studies in order to check their performance. Finds largest errors in predictive techniques are associated with estimation of site wind speeds and window-wall infiltration characteristics. States that techniques available are not suitable for the assessment of running costs or environmental performance standards under normal conditions, forwhich a more sophisticated meteorological input is required.