The functional flexibility and the construction quickness of housing systems are becoming a necessity. The traditional living concepts are put in crisis from frequency and intensity of natural disasters, extreme weather events, migrations and urbanization. In this context, the paper's idea is to define a temporary housing system, based on a multi-disciplinary design approach. The complex aspects related to the architecture, the structure and the energy are interconnected among them. The result is a prefabricated modular wood-house system, characterized by construction quickness, functional flexibility and energy efficiency. Leitmotif of the project is the sustainability, applied in the various aspects that characterize it: energy efficiency, building components prefabrication (to make easy their reuse and recycle), wood as building material in its various technologies, indoor comfort and healthiness. Lacking specific targets towards which address the design path, or rather not knowing the end-users, nor the location of the building, it has been maintained a degree of freedom, both at architectural and at structural level. The overall aim has been to design a prefabricated modular wood-house system, structurally and functionally autonomous, and spatially combined in several living units to form composite configurations. The paper describes the main features of the Living Box and the results of its technical analysis.