The use of redundant computational nodes is a widely used design tactic to improve the reliability of complex embedded systems. However, this redundancy allocation has also an effect on other quality attributes, including energy consumption, as each of the redundant computational nodes requires additional energy. As a result, the two quality objectives are conflicting. The approach presented in this paper applies a multi-objective optimization strategy to find optimal redundancy levels for different architectural elements. It is implemented in the ArcheOpterix tool and validated based on a realistic case study from the automotive domain.