The Timisoara Masterplan consultation for the new General Urban Plan of the second largest city of Romania is an interesting case study which illustrates how IMM (Integrated Modification Methodology), considering the city as a complex adaptive system (CAS), works for improving the urban quality as well as the city’s environmental and energy performance exploring the relationships between urban morphology and energy consumption. According to this theory, the city, studied as a complex adaptive system, is not solely a mere aggregation of disconnected energy consumers and the total energy consumption of the city is different from the sum of an entire building’s consumption. So the energy efficiency of every element has to be optimized in a way that improves the other elements of the energetic performance as well. The project based on the re-development of an important part of Timisoara shows that morphology plays an essential role for any energy-saving policy, urban efficiency.