AbstractRenovating the existing building stock is well recognized in the construction industry as a very important issue. While the number of new buildings annually provides maximum 1% to the building stock, the other 99% represent buildings which are already built. Studies show that the environmental impact to extend the life of a building is definitely smaller than that of demolition and new construction. Recent figures suggest that the residential sector can provide significant reductions in energy consumption.As many vital decisions are taken in the early stages of the refurbishment process, planners need tools that will help them create better and more sustainable retrofitting projects based on the improvement of the building energy performance.This study describes a methodology to support decision making in the retrofitting of the existing building stock of the Leopold Quarter in Brussels to enable the development of an integrated strategy for different cases and specifications. It is intended that the planners know since an early stage, the energy impact of the project according to the selected interventions.All the proposed retrofitting strategies are compiled in a database that is the basis of the tool named TCS Matrix (TCS stands for: Typology, Component, Solution).This paper provides an insight of the methodology to create the aforementioned databases as well as a series of scenarios that supposes a first step of the aimed methodology to identify in an early stage the best solutions for this specific part of the building stock to achieve the energy efficiency targets defined by the Energy Performance of Buildings Directive.