Real estate portfolio owners face a huge challenge with the combination of the necessity to refurbish ageing buildings inherited from the booming construction period of 1950 to 1980 and the need for decarbonization of the heating systems of the building stock to preserve the environment. Many property owners facing this challenge do not have a clear overview of their portfolio and do not know where and how to start renovation work on their existing build-ings, and lack basic instruments to help them in the strategic planning phase. A very simple and transparent digital tool has been developed by the HES-SO /HEPIA, Ge-neva, on behalf of a real estate foundation in Geneva to give its board a clear vision on the Foun-dation assets and help it to define intervention priorities amongst its building. This tool, based on a multicriteria and interdisciplinary approach, is be one of the instruments that can help real estate portfolio owners to tackle the challenge they are facing today, in a simple and autonomous way.