At a time when there is mass awareness of the impacts of climate change, mainly due to the increase in carbon emissions, the reduction and control of energy consumption represent major challenges for the future. Taking up this challenge will help to contain the rise in climate change. This project speeds up the identification of sources of energy savings in existing buildings using advance computing methods and will enable the effectiveness of the technical solutions proposed by architects and engineers to be virtually tested before any improvement work is undertaken. This project makes it possible to make the expected results more reliable with regard to the theoretical calculations corrected by integrating the data from the physical sensors in place in the buildings into the equations. Finally it makes it possible to estimate, with almost absolute reliability, the impact of the reduction in the carbon footprint linked to the proposals for the resulting modification work.