The worlds population is aging at an unprecedented pace. Aging society is not only a severe crisis in the developed world such as Germany and Japan, but also a rigorous challenge in emerging economies such as China. Many age-related diseases are fostered by the lack of physical, cognitive, and social activities. Increasing the activity level has many benefits for the elderly and can improve their independence. The research project REACH (funded by European Unions Horizon 2020 Research and Innovation Program under grant agreement No. 690425) aims to develop a service system that will turn clinical and care environments into personalized modular sensing, prevention, and intervention systems that encourage the elderly to become healthy through activities (e.g., physical, cognitive, socializing, personalized food, etc.). As a core research partner, the Chair of Building Realization and Robotics at Technical University of Munich developed a series of Personalized Intelligent Interior Units (PI²Us), which are a special type of smart furniture, that materialize the REACH concepts and functionality seamlessly into the different REACH use case settings. Specifically, the design and functions of the PI²Us, which consist of the PI²U-SilverArc, PI²U-MiniArc, PI²U-Bed, and PI²U-iStander, will be described in detail. In addition, a modular apartment integrating all PI²Us and key technologies in REACH is designed and simulated to create a total interior living and care environment for elderly users. Due to its modularity, parts of the apartment can be easily adapted and rapidly deployed in different REACH use case settings in four European countries, which will then help the REACH consortium execute a series of testing activities. In conclusion, this research project provides a systematic and innovative example for the world to mitigate the impact of aging society.