The aim of this paper is to introduce a methodology which enables to revise the limit values of the heat transfer coefficient in accordance with the building form with respect to thermal comfort and energy conservation. In this study, the building form is represented by the ratio of the total facade area to building volume (A/V). As the building form and the heat transfer coefficient (U value) of a building are the most important parameters affecting indoor climate, they have been taken into consideration in detail. The proposed methodology enables to determine the limit values of the building envelope heat transfer coefficients on the basis of A/V ratios and other design parameters affecting indoor thermal comfort and energy conservation such as orientation, window type, optical and thermophysical properties of the building envelope. The methodology has been applied for temperate and cold zones of Turkey and the results of the application are given by sample graphics in the paper. (C) 2002 Elsevier Science Ltd. All rights reserved.