Critical Performance Aspects of Retrofitting Apartment Buildings Using a Multifunctional Façade System

There is huge market potential for energy refurbishment solutions in European buildings. This paper analyzes the challenges related to using a multifunctional energy efficient façade system, the “Meefs” system, in retrofitting multi-family apartment buildings. Similar challenges often occur also in other comparable façade renovation solutions. The focus is on hygrothermal performance even as other aspects are also discussed. After introducing the hygrothermal performance challenges of the Meefs system, numerical case analyses are performed in three different climatic conditions. The results for 26 cases are presented. A core result is that the drying of any exterior renovation system is mandatory to guarantee safe operation in different European climate conditions. This emphasizes proper design needs in all climates. Based on the analyses, design recommendations can be given for the Meefs system. In Central and Northern European climates, the system contains challenges which may hinder implementation in practice.