A renewed interest in considering solar energy in the design process of new buildings has favoured the development of simulation software that estimate available solar energy so as to contribute to natural lighting and energy production. The input data required by this type of software are information regarding luminance or radiance angular distribution over the sky dome. However, such information is recorded at a handful of locations being therefore necessary to use estimated values. To that purpose, several models have been developed for both luminance and radiance estimation. In this paper four of these models are analysed and their ability to estimate radiance values is validated using data recorded at two different locations. For some of the models, different versions are considered. In addition, the effect of different data calibration procedures on model performance was investigated. On the whole, it can be concluded that results obtained by the four models are quite similar. However, depending on the version applied or the sky condition analysed, the best performance is derived from different models. (C) 2011 Elsevier Ltd. All rights reserved.