Due to extreme climate change events, achieving indoor thermal comfort has become a significant challenge in remote desert areas; particularly with the increasing number of energy shortages in these areas. This study uses participatory action research methodology by means of an occupant centred approach for the design and construction of a Trombe wall system, suitable for passive heating and cooling in hot arid climates. The Trombe wall is used as a low-tech retrofitting passive solution to provide deprived communities in off-grid desert areas with a better indoor climate. The paper presents data from one year of monitoring and post occupancy evaluation for the Trombe wall installed as a retrofit in a residential unit in Sinai, Egypt as a proof of concept. Available affordable local materials were of main concern because of the project's remote location in a mountainous desert area with very limited natural resources. The idea was to involve the local community in the different phases of the project, then train them onsite on how to use the Trombe wall system. Results indicate that the use of the Trombe wall did in fact enhance indoor heating and cooling loads. In addition, the direct involvement of the local inhabitants proved to have a positive impact on the Trombe wall's performance and efficiency. The discussion elaborates on key lessons learned and challenges faced from the urban living lab experience presented in the study. Lastly, recommendations for further implementation of the passive Trombe wall system are presented.