Products with multiple use phases have to be considered regarding new economic and environmental pressures. Therefore, the related complex life cycles of (re)manufactured products have to be modelled and assessed by design teams for a better understanding of their performance. The present study shows how to establish the models and how to compare the environmental assessments of remanufactured products life cycles and product system-services (PSS) vs. classic product life cycle. The objective is to provide easy to use methods and tools for designers to allow them quantifying the environmental benefits related to the use of a closed loop strategy. The results can be further used in simulation, to evaluate the environmental performance of different product life cycle end-of-life scenarios.