Since the mid-1970s, urban development in Egypt has sprawled far from the distinguished compact arid built environment, as the court-yarded housing typologies that completed the vernacular picture of desert architecture have been discarded in the early 20th century. This has motivated urban microclimate research in Egypt. The main objective was initially to improve outdoor thermal comfort. Therefore, Egyptian research started with assessing different existing patterns for the sake of climate responsive and sustainable urban design practice characterized with low carbon, thermal comfort and energy efficiency in such a hot arid conditions. That is why the review workflow of this article has followed a design progress workflow that led to solving design complexities with regard to generating housing urban forms on a microclimate basis rather than an article regular review workflow in order to extract the research gaps and conclude insights. After discussing a general framework for generating housing sustainable design identified from the concluded gaps, the main conclusion is a vision and a call to integrate the Urban microclimate-Building passiveness-Renewables design dimensions, UBR, towards the evolution of a new era of energy efficient housing typologies and a 5th generation of Egyptian sustainable cities where the 1^st generation of new Egyptian cities started 1970s.

Heritage buildings are significant historical and architecture added value, which requires deep and precise preliminary brainstorming when considering upgrading or retrofitting these valuable buildings. In this study, we opted to highlight some passive design architecture interventions to improve the thermal comfort and the required cooling energy for buildings. The Murabba Palace in Riyadh was selected as a case study. DesignBuilder software was used to evaluate the energy performance of ten passive architectural design alternatives throughout different seasons in an attempt to improve the energy performance and thermal comfort of heritage buildings. The ten passive design scenarios encompassed double low-E glass, double reflected glass, double low-E glass and double wall with an air gap, double low-E glass and double wall with thermal insulation, double low-E glass and double wall with lightweight thermal insulation, double low-E glass and double wall with sprayed foam insulation, double reflected glass and double wall with an air gap, double reflected glass and double wall with thermal insulation, double reflected glass and double wall with lightweight thermal insulation, and double reflected glass and double wall with sprayed foam insulation. The results show that using double low-E glass and applying a double wall with polystyrene thermal insulation can enhance the thermal comfort inside the building and reduce the energy performance and CO₂ emissions to 17% and 9%, respectively.

Because existing buildings occupy most of our built environment, there is an urgent need to upgrade them considering building sustainability criteria. Therefore, many optimization models were proposed to find the optimum upgrading solution that improves the building sustainability while minimizing its costs using traditional sustainability rating tools [e.g., Leadership in Energy and Environmental Design (LEED) (US), Building Research Establishment Environmental Assessment Methodology (BREEAM) (UK), and others]. The variations among these tools hinder their application outside their original countries, calling for global tools. Therefore, this study contributes to the knowledge by developing a novel multiobjective optimization model to solve the life cycle cost (LCC)-sustainability trade-off for building upgrading using a generic sustainability rating tool. This tool includes seven sustainability criteria and 29 subcriteria, resulting in 134 decision variables. The proposed model finds the near-optimum upgrading solutions that minimize their LCC while improving the building sustainability using the multiobjective artificial immune system algorithm. The model was applied to a real case study of a large building in Montreal, Canada. The obtained solutions covered almost all the ratings ranges from pass to outstanding and showed the trade-offs between the building sustainability and LCC. This research is a step toward adopting a global sustainability rating tool to find the optimum building upgrading solutions that can address the regional limitations of the traditional rating tools.