In order to take advantage of the local climate many passive solar design techniques were applied to reduce buildings energy demands. In term of reducing heating demands, the Trombe wall system appears as one of these effective passive techniques providing that it was properly conceived. In this study a numerical model of a Trombe wall system was developed using TRNSYS software and validated by a small scale experimental prototype, located at the Laboratory of Thermal Processes of the Research and Technology Center of Energy (CRTEn) of Borj Cedria. This model was then adopted for the numerical investigation of Tunisian typical buildings. The results of the simulation show that approximately 77% of the total heating demand of a 16 m(2) non-insulated simple typical Tunisian building, can be realized by a vented Trombe wall of 8 m(2). A 97% reduction of the annual heating loads was attained by a 6 m(2) Trombe wall area when the external walls of the considered simple building were double walls insulated by 5 cm of expanded polystyrene. (C) 2014 Elsevier B.V. All rights reserved.