More than 95% of multi-story residential buildings in Austria are currently predominantly constructed with conventional mineral construction materials. This fact combined with the increasing demands for a healthy residential living atmosphere demonstrates the great potential for using ecological materials. Life cycle assessments provide information on the ecological performance of buildings, but the corresponding economical aspects are not considered. Nevertheless, the economic aspects of a certain draft are important to clients and designers. Therefore, simplified assessment-tools are needed that take into account the ecological impact as well as the building costs. This paper presents the results of an investigation supplemented by a case study of a multistory residential building, which was finished 2016 in Austria, illustrating the differences between the state-of-the-art material selection and ecologically optimized alternatives. The ecological impacts and the costs for the selected building-system were determined based on the case study. Subsequently, ecological optimization potentials were identified according to the environmental indicator OI3. Finally, the effects on component and construction costs were evaluated. The steps of this simplified process reveal the interdependency between ecological aspects and the costs of materials. This procedure represents a decision-making tool that can be used by clients as well as designers. The results of this research emphasize the large environmental impact improvements with little expenses when implementing sustainability in multi-story residential buildings as a crucial part of a green design.