Retrofitting the suburbs: Insulation, density, urban form and location

The effects of urban sprawl have been well documented, particularly regarding energy consumption. Suburban neighbourhoods are known to be energy inefficient and urban sprawl is considered as a major issue for sustainable development. To improve the energy efficiency of existing suburban urban fabrics is a major challenge that must be addressed to favour a sustainability transition of our built environment. In this context, this paper aims at investigating several scenarios that could be developed to improve the sustainability of existing suburban neighbourhoods: three main types of scenarios (building insulation, density, and urban form) and twelve sub-scenarios, which are focused on the possible evolution of the existing suburban building stocks, are proposed. Quantitative methods developed in previous research are used to assess and compare building and transportation energy consumption of a representative suburban case study. This application aims at investigating two main research questions: (1) "how to intervene in suburban neighbourhoods?" and (2) «where to intervene?" The main results of this application, which are focused on energy efficiency, are then studied in a larger framework to highlight their opportunities and constraints. The main findings of the paper are that, beyond the traditional polarisation of the debates on the energy efficiency of our built environment between the “compact” and the “sprawled” city, a new pragmatic paradigm, which is focused on the smooth densification of existing suburban neighbourhoods, can make them evolve towards greater sustainability.