Inhabitants play a key role in the global energy consumption of buildings. However, it is difficult to motivate people to be concerned about energy management. Our objective is to make energy consumption visible by simulating the energy impacting behaviours of inhabitants by using Energy Plus and a 3D virtual environment. This will make energy consumption more obvious to people due to the use of a serious game. The nature of this game is exploratory where the player's knowledge about energy consumption is enriched as he plays the game. In this paper a methodology for building a serious game for energy management is proposed. In order to analyse the impact of occupant's behaviour the game is coupled with EnergyPlus. The Functional Mock-up Interface (FMI) standard is used for coupling these different tools. Since the occupants experience the impact of their different behaviours on energy consumption, the game creates an awareness about energy management and motivates the occupants to save energy.