The present invention relates to a system for analyzing building energy consumption and particularly to a web-based system for remotely analyzing building energy consumption information in real time that can remotely collect and store building attribute information, facility operation and status information, energy consumption information, environment information and real-time commissioning information and the like of a plurality of buildings in real time, provide and manage various services for energy efficiency improvement based on such information, generate building energy efficiency improvement plans (actions) automatically by performing services according to a manager's selection and using inference devices based on the execution result to optimize energy consumption and efficiency of a building and energy facilities.