This proposal focus on the potential of the existing upgrade process in achieving the 20-20-20 goals, as are the biggest energy consumers, the most significant built area and the better placed within our cities. These frequently lack basic maintenance and need intervention, but include within themselves a vast amount of incorporated energy and centuries of construction knowledge. Beyond the advantages that may result from re-attracting people back into the city centre, existing can also have positive bounce-back effect on the reduction of the energy needs related to transportation, as demonstrated in studies that alert to the impact of the sprawl in the total energy use. As buildings account for 40 % of total energy consumption in the Union, the better performance of this sector has a significant role, remembering that these requirements shall take account of general indoor climate conditions, in order to avoid possible negative effects such as inadequate ventilation, as well as local conditions and the designated function and the age of the building (1). The importance of upgrading the existing resides on the fact that new represent only approximately 1 or 2% of the total usable area, an estimate that is bound to decrease due to the current construction crisis. While the recent tend to be more efficient, the numerous existing are important stakeholders due to their massive consumptions and incorporated energy. The ongoing Annex 56 on Energy & Greenhouse Gas Optimized Building Renovation assumes that Current standards do not respond effectively to the numerous constraints imposed by existing and in many cases, the requirements result in very expensive measures and complex procedures, seldom accepted by occupants, owners or developers. It is then urgent for the new standards to respond to constraints and to develop good practice guides that integrate appropriate, applicable and cost effective technologies (existing or emergent ones) (2). Many existing that we still recognize assimilated the introduction of water networks and wastewater disposal, electricity and artificial lighting, new people and new uses. It is now time to help to embrace the XXI century revolution of smart cities while keeping our visible memory alive.