This paper presents a method to quantify the potential of facades and roofs located in urban areas for active and passive solar heating, photovoltaic electricity production and daylighting. Solar irradiation and illuminance values obtained through numerical simulations form the core part of the method. Results obtained from a case study comparing different building layouts at constant density in Fribourg (Switzerland) reveal large variations of the potential for solar energy collection on buildings facades. Thus, the proposed method could greatly help to optimise solar collection still at the early urban planning phase. (C) 2004 Elsevier B.V. All rights reserved.