Buildings with architectural constraints and recognized historical values entail careful design process, especially, when the aim is to improve the energy efficiency. Foreseeable interventions consist of preservation and improvement of building envelope energy performance as well as the adaptation of the built environment to modern use and its accessibility. The compatibility between the aforementioned constraints and its future more sustainable use represents the crucial challenge. In this paper, feasible interventions on the dwellings from the 40’s in Borgata Trullo, Rome were designed and analyzed. Public housing asset is an interesting environment to test a sustainable holistic approach due to its homogeneity in terms of building technology solutions and typologies. Furthermore, the absence of public funding made more difficult the ordinary and extra-ordinary maintenance processes. So, the approach accounts for the age of the building along with the subsequent reduced energy performance as well as the architectural values to preserve. The proposed energy retrofitting measures are related to the building envelope, in the installation of insulation layers, the substitution of windows and improvement of HVAC systems to enhance energy efficiency. Besides the case study, design guidelines were presented to help the stakeholders in compatible and sustainable interventions. New HVAC solutions showed high gains in energy saving even if building envelope modifications were limited by the willing to preserve the cultural heritage values. Therefore, a virtuous restoration can address effectively current energy efficiency targets.@en