Two Case Studies in Energy-Efficient Renovation of Multi-family Housing: Explaining Robustness as a Characteristic to Assess Long-Term Sustainability

This study addresses two energy efficiency approaches to renovation of multi-family housing in Sweden aiming at a better understanding of robustness as a building characteristic especially in terms of energy performance of buildings and indoor air quality (IAQ). Robustness could be generally defined as the characteristic of measures by which the building or the system lives up to its design purpose in a real life situation. The performance of some systems in operational situation is not the same as their expected performance during the design phase. This could be caused by poor assumptions during modeling or disregarding users’ behavior. In case of energy efficient buildings such misestimation can result in vulnerable measures which would affect energy objectives of the design. Thus, to achieve sustainable architecture especially in a long-term perspective, applying more robust measures would eliminate vulnerability of design to future changes and enhance durability and reliability of building. Solar houses in G\ue5rdsten and passive houses in Brog\ue5rden have been chosen as two different approaches to renova-tion of multi-family housing with energy efficiency (EE) objectives. The two cases have been analyzed using an analyti-cal framework which has been developed based on the findings of this study to assess the robustness of applied EE measures. Adaptability, Redundancy, preference for passive techniques, users control over IAQ, transparency of systems to users and maintenance facility have been considered as the main criteria for robustness analysis and the performance of cases has been studied in relation to major factors likely to face uncertainties such as household appliances, occupant behavior, maintenance support, energy sources, technical systems, envelope quality and climatic conditions