A Building Energy Management System (BEMS) is a fundamental computer-based system aiming at optimizing management of building assets towards energy savings without compromising occupants’ comfort, while developing a potential to apply demand response strategies. Building energy management systems nowadays have evolved and comprise of heterogeneous components and complex architectures. Building management systems monitor indoor building conditions while controlling building assets like lights, security systems, and heating and air ventilation’s systems. Furthermore, to facilitate the specification of the building’s attributes for building energy management systems the use of semantic technologies is needed within building energy tools. This paper undertakes a comprehensive review of Building Energy systems in the context of Internet of Energy.