Environmental performance assessment: A comparison and improvement of three existing social housing projects
The energy consumption of buildings accounts for 22% of total global energy use and 13% of global greenhouse gas emissions. In this context, this study aims to evaluate the environmental performance of three social housing designs located in emerging economies by analyzing sustainability indicators adopting different technical solutions. The analysis incorporates eleven construction strategies to improve the environmental performance of the buildings. The performance assessment is analyzed by using the EDGE (Excellence in Design for Greater Efficiencies) Methodology.
Therefore, this study aims to help identify the construction strategies, with the aim of improving the operational energy performance (kWh/year/m2 floor), operational CO2 emissions (CO₂ eq/Year/m2 floor), embodied energy (MJ/m2 floor) and operational water consumption of housing (m3/year/m2 floor). The results showed that when the technical measures are implemented, the energy demand decreases by 38.52% in Case A, 19% in Case B, and 41% in Case C. The embodied energy savings in materials in Case A 3%, Case B 0%, and Case C 36% Regarding water consumption, the demand decreases by 46%, 4%, and 12% in Case A, B, and C respectively.
Recent demographic trends are indicators of the potential future challenges to sustainable development. In 2019, the Department of Economic and Social Affairs of the United Nations reported that the global population will reach over 8.5 billion in 2030 (United Nations Human Settlements Programme, 2003). In the housing sector, the new designs should assess all the phases of the life cycle of the building to mitigate the negative environmental impact (Palmer et al., 2006).
However, discussion on dwelling rehabilitation versus its demolition and new construction has been increasing in intensity since the end of the twentieth century, especially due to the necessity for the regeneration of urban centers caused by the great migration from rural to urban areas (Denhez, 2007; Laefer and Manke, 2008; Rakhra, 1983).
In several studies, it is demonstrated that even with a severely damaged building, the repair and retrofit work incurs a lower economic and environmental impact than new construction (Kohler and Hassler, 2002; Itard and Klunder, 2007; Goldstein et al., 2013; Ferreira Sanchez, ´ 2015; Oti et al., 2016). The building reuse projects eked out carbon impact reductions that seemed small when considering only one building. Still, they showed substantial savings on a medium to large scale (Alba-Rodríguez et al., 2017). Several studies find that building reuse can avoid unnecessary carbon outlays and help communities achieve their near-term carbon reduction goals (Alba-Rodríguez et al., 2017).
The construction sector should take an active role in encouraging environmental protection, economic growth, and social advancement is crucial to empower technical solutions at the early design stage to reduce operational expenses and environmental impact and to avoid future renovations and investments (Gan et al., 2017; Liu et al., 2020).
In this regard, a rapid large-scale housing strategy called incremental housing has been applied by some architects to provide temporary and permanent housing to low-income users after different natural phenomena events and the increment of house demand in cities (Askar et al., 2019). Incremental housing is a step-by-step process: it starts with a starter core shelter.
The starter core could be a kitchen and a bathroom unit or solely an empty lot with a utility connection potential. This incremental housing method has displayed technical advantages and disadvantages through the years. Some disadvantages are, e.g., the lack of understanding of users’ needs (spatial design), the poor environmental performance, the difficulties of making urban services accessible, the poor construction quality causing health problems, and the high cost of electricity (Marinovic and Baek, 2016; Azizibabani and Bemanian, 2019; Martins and Saavedra Farias, 2019).
This paper aims to answer two main questions concerning environmental performance related to social housing performance, How to improve the existing social housing design to consequently improve the building’s environmental performance? And is it possible to reduce operational expenses of the social housing designs by improving the building’s environmental performance?