In the current context of ongoing search for improvement of energy performance, the management of buildings’ energy performance has become a very important stake. Openergy aims to revolutionize the energy monitoring of buildings thanks to dynamic thermal simulation. The calibration of the simulation consists in adjusting different input parameters in order to have results close to reality. This convergence is generally guided by an expert of the field, but it aims to become automatic, in order to ease the use of the simulation. This method could even be adapted for energy mutualisation between different buildings.