As a part of a bigger research project to create a detailed strategy to achieve Zero-Energy level in Egyptian office buildings, This Research paper mainly focuses on the impact of Building-Envelope design alternatives on the building “Cooling, heating and lighting” energy consumption through an extensive simulation process using OpenStudio interface of EnergyPlus software. A medium size office building model was created as a case study. A variety of different scenarios for window to wall ratio “WWR”, building orientations, blind length & tilt angle, window types, wall types and roof types were studied and their impact on the building energy consumption was analysed. 50 cases for Design-alternative combinations were studied in 2 Egyptian cities “Cairo and Alexandria” located in 2 different climate zones. Applying proposed strategies can achieve Energy savings for [Heating+ Cooling+ lighting] by more than 6 1 % in 40%WWR case and 46% in 20% WWR case. After applying the passive strategy an active solar system was proposed after analysing 6 cases of PV scenarios. The building could reach positive energy level through the applied strategy. This research will be continued to provide a full zero-energy building strategy for Egyptian office buildings that shall include a full life cycle cost analysis.