Given the challenges to design Net Zero Energy Buildings (NZEBs) the use of Building Performance Simulation (BPS) tools during early design phases has been indispensable. In this context, BPS techniques can be supportive when integrated early in the design process. However, architects suffer from BPS tools limitations during this decisive phase that addresses more the building geometry and envelope. To identify those limitations and as part of the International Energy Agency (IEA) Task 40: Towards Net Zero Energy Buildings, this report compares ten early design BPS tools. The aim is to define the potential of using and integrating the tools by architect during the design of NZEBs. The examined tools include HEED, e-Quest, ENERGY-10, Vasari, Solar Shoebox, Open Studio Plug-in, IES-VE- Ware, DesignBuilder, ECOTECT and BEopt. The comparison is based on five criteria including usability, optimization, interoperability, accuracy and design process integration of the tools. The results describe tools limitations and major requirements to meet the NZEBs objective implications.