A Building Energy Management System (BEMS) is a computer-based centralized system that helps manage, control and monitor particular engineering services within a building or group of buildings. It can limit energy costs and labour requirements and provide a more comfortable environment. BEMS have evolved form a simple supervisory control tool to an integrated computerized control and monitoring system. The purpose of this guide is to provide assistance to project sponsors, property managers, specifiers, designers, energy managers and operators, in the procurement, use and maintenance BEMS.