The future of masonry buildings with heritage values is certain - the investments in making such buildings energy-efficient during renovations to meet the energy consumption requirements will increase over the next decade. However, decision makers fail to address the concerns of each project actor and give specific answers on how basic requirements on such historical buildings can be implemented. This paper proposes a new multi-criteria group decision-making method for the thermal renovation of masonry buildings. The aim of the proposed method is to rank different renovation solutions. The method uses; the structured group interaction method Delphi to define the evaluation criteria and the thermal renovations solutions, Swing method to facilitate the process of the determination of the criteria weights, the group decision support system (PROMETHEE GDSS) to reach a global ranking of the renovations solutions, PROMETHEE V to introduce additional constraints, as well as the Graphical Analysis for Interactive Aid (GAIA) analysis to get a better understanding of conflicts and similarities between the criteria and among the decision makers. We proceed to exemplify by means of a real-life case project in Algeria and offer suggestions on what front-ended stakeholders could do to reduce the energy consumption in masonry buildings. (C) 2016 Elsevier B.V. All rights reserved.