In response to the Ageing of our Society, a new paradigm is evolving that promotes healthy ageing and independency through self-care and wellbeing. The role of the living environments is crucial in the Ageing Society to promote wellbeing. Besides, elderly contribution through social participation is essential for their integration and inclusion in society. This thesis explores the case of Cooperative Housing for elderly in Sweden, a concept that promotes the participation of elderly in the design of their habitats. The research is oriented towards a smoother inclusion of elderly in participatory processes aimed at developing sustainable and need-satisfying habitat solutions for elderly. To do this the author explored how the concepts of PSS, Design Thinking, Human Needs and Needfinding could inform the design of those participatory processes. Based on the results of interviews, questionnaires and three case studies on Cooperative Housing, a set of three distinguished types of recommendations was developed to guide the design of future participatory processes: overarching models, process enablers and specific methods and tools for each of the process phases. Mainly, the discussion focuses on the concepts of PSS, human needs-centered design and sustainability, and how those can enable a smoother inclusion of elderly.