Abstract. It has been noticed that research is increasingly focused on exploring opportunities to use environmental devices of traditional origin to create more sustainable contemporary buildings. Unfortunately, this “neo-traditional trend” (Abdelsalam et al., 2013) is hindered by the performance of vernacular solutions, which are unable to meet the new needs of contemporary society. Advocates of this ideology believe that this situation is due to a lack of knowledge of these vernacular devices. From this point of view, this paper aims to establish a better knowledge of them for the purpose of improving their performance within contemporary buildings. Thus, it presents a comparison study between the traditional architecture represented by the Algiers Kasbah house and the M’zab valley house in Algeria. The choice of the case studies was made in light of the fact that notwithstanding the very opposite environmental contexts of each case study, they belong to the same typology of traditional houses called “house with wast ed dar”. In fact, they share several similar environmental features such as the patio and the terrace. Even though initially there appear to be many similarities, some aspects of these devices vary from one environmental context to another. Therefore, this paper investigates the urban layout in which the houses are built as well as the principles of design and building materials in order to explore the impact of the physical and climatic conditions, referred to in this article as the “geo-climatic environment”, on the environmental devices developed by each house. It compares the performance of these devices and how they respond to their geo-climatic environment in order to better understand their functioning mode which is the key of their successful adaptation to each environmental context and which could be the key to any future use of these vernacular devices in contemporary buildings.