This paper focuses the attention on the drawbacks and abilities of wall-function techniques through an analysis of well-known wall-functions from literature. Besides this. sonic deeper analysis of these tools by means of physical and numerical considerations are carried out in order to improve their limitations when they are applied to predict heat transfer and fluid flow. Accuracy, grid-sensitivity, numerical behaviour and verification of numerical simulations arc key aspects in this paper. The main purpose is to obtain tools which are able to predict both fluid flow and heat transfer with low CPU time consumption, reduced grid-sensitivity and a relatively good accuracy. (C) 2008 Elsevier Ltd. All rights reserved.