Vernacular buildings in Egypt express a variety of passive low-tech approaches in design and construction to achieve human comfort and fulfil inhabitants' requirements. They have been devised to suit living in regions where local inhabitants had to invent various passive building strategies to live under severe local climatic conditions without depending on fossil fuels. This paper discusses a retrofitting approach for off-grid vernacular buildings in the Western Desert of Egypt. The study hypothesis argues that, when retrofitted and equipped with renewable energy solutions, vernacular structures can act as nearly zero energy buildings. A post occupancy evaluation was used as an assessment tool for two pilot projects that served as case studies. Results showed that combining vernacular passive strategies with affordable active renewables such as roof top solar panels results in a hybrid energy efficient retrofitting solution for deprived off-grid vernacular buildings. The intention is for the results to act as a basis for future retrofitting that would take into account the challenges and obstacles inherent in such work. This is an aim capable of contributing to a reduction of energy consumption that would also encourage retrofitting using renewable solutions for existing housing stock in Egypt.