Project Leader: Professor Adisa Azapagic
Project Duration: January 2009 - January 2012.
The residential construction sector in the UK plays an important role in society’s wellbeing as it provides shelter, employment and promotes economic growth. However, the sector has been identified as a large contributor to climate change, resource depletion and is associated with different socio-economic issues such as fuel poverty and house affordability. The residential construction sector is growing quickly due to a high housing demand, as will the associated impacts unless significant changes are made. Several studies have assessed the environmental impacts of the residential construction sector, while the social and economic aspects of sustainability are often ignored but are equally important for sustainable development.
This work has developed a sustainability assessment framework capable of addressing the environmental, economic and social issues of the residential construction sector supply chain, using a life cycle approach in order to contribute toward an improved understanding of the current and future trends in the sector. The methodology developed has been applied to the residential construction sector in the UK and demonstrated through three case studies of conventional, passive and zero-carbon houses as well as a sustainability assessment at the sectoral level. The main stakeholders identified here are construction companies and workforce, home owners and occupiers, suppliers, local authorities and the government. The main sustainability issues are resource depletion, waste generation, environmental impacts such as global warming (GWP), ozone depletion, house price and affordability, contribution to GDP, provision of employment, health and safety, impact on local communities and business ethics.
The assessment tools used to assess the environmental and economic sustainability are Life Cycle Assessment (LCA) and Life Cycle Costing (LCC), respectively. Social sustainability has been assessed using different social sustainability indicators applicable to the residential construction sector. LCA results indicate that zero-carbon houses have the lowest GWP of the three house types considered, being 71% lower than for the conventional house, compared to a 59% reduction for passive houses. However, passive houses have a better overall environmental performance as they have the lowest impacts for most environmental impact categories. LCC results, on the other hand, indicate that the total life cycle costs for zero-carbon houses are 21% higher than for conventional houses because of the additional cost of renewable technologies, while for passive houses costs are comparable to conventional houses.
At a sectoral level, zero-carbon houses can achieve reductions of 13% of the sector’s annual GWP compared to conventional houses, however this will cost the residential construction sector an additional £3 billion per year. The construction of passive houses will cost an additional £1 billion per year compared to conventional houses but can help by reducing the sector’s annual GWP by 10%. This study shows that the current state of the housing sector is environmentally unsustainable and urgent changes must be made in the way houses are constructed and managed. However, the residential construction sector must overcome many socio-economic barriers before introducing low-carbon houses on a large scale.
This project is completed and the PhD dissertation can be found here.