This paper discusses the use of exploratory scenarios with environmental conditions on a case study in the Dutch context. The goal is thereby to assess the robustness of design alternatives during the lifetime of its building components. During building design it is common practice to use "normative" scenarios to prove compliance with design standards. The use of "exploratory" scenarios is less common. However, it is hypothized that the use of exploratory scenarios is a meaningful alternative, if no information is available on the uncertainty of input data such as climate and building use. This paper focusses particularly on the performance variability due to climate change. The European Commission targets a 20% reduction of CO2 emissions, a 20% increase of energy efficiency and a 20% increase in the use of renewable energy by 2020 still providing comfortable conditions within the buildings. As neither, building use nor environmental conditions are constants, it is necessary to quantify their influence on the energy use over the lifetime of its building components and subsequently on achieving the overall aim. For the designer it is impossible to assess the contribution of his/her individual building project on achieving the goals posed by the European Commission. However, considering the performance of the building and its components under potential future conditions, conditions deviating from the design conditions, has the potential to support design by supporting the selection of design alternatives, provide comfortable conditions and reduce energy demand during building operation. To integrate building use and environmental conditions into the computational performance assessment, their stochastic character needs to be taken into account, which is rarely possible due to limited availability of data. Still, in the absence of stochastic input data the use of exploratory scenarios represents a feasible alternative to map the variability of building use and environmental conditions. The paper concludes that ...