Holistic approach for energy retrofit with volumetric add-ons toward nZEB target: Case study of a dormitory in Athens

This paper proposes a novel multistep approach for comparing several architectural solutions with the aim to create additional volumes on existing buildings by means of the façade transformation. The nearly zero energy standard is the objective of the designing and the criteria for the comparison take into account the minimization of economic impacts and the maximization of comfort conditions for the occupants. An innovative SWOT matrix is proposed for evaluating, with multidisciplinary approach, the results of the refurbishment design. The internal strengths and weaknesses are referred to the building occupants, while external opportunities and threats are referred to the whole society. The proposed approach is applied to the B Building FEPA of the student dormitory in the National and Kapodistrian University of Athens in the frame of a research project financed by HORIZON 2020 funds. With reference to the case study, an increment of around 22% of living space is achieved with energy saving and polluting reduction of around 90%; at the same time the amenity of the outdoor environment, the seismic security, the global comfort are improved. The results of the case study allow to demonstrate how the volume add-ons technique can bring many benefits, not only on the energetic point of view, in the refurbishment of the existing building stock. The awareness of these advantages could encourage occupants, tenants and communities to participate actively in the designing process, and it could be accelerate the achievement of the nearly zero energy standard for the existing building stock. This is the future goal for the sustainable development of the building sector.