In the attempt to adhere to the UK’s 2050 Net-Zero Strategy, more attention has been given to energy-centric decision-making over the regeneration of housing estates. Whole Life Carbon Assessment (WLCA) is the methodology used for the evaluation of the overall carbon dioxide equivalent (CO2e) emissions of building projects over their lifecycle. The WLCA studies are mostly not understood by different stakeholders and are less effective in reducing the Global Warming Potential (GWP) impacts in the development of regeneration scenarios. This paper is part of a larger study on a multistakeholder lifecycle-based sustainability assessment framework and aims to further explore whether retrofitting can outperform the existing and new build scenarios for lower GWP impacts, and intends to examine the use of WLCA for the development of a regeneration scenario. The research consists of a single-case case study employing co-design workshops, surveys, and WLCA experiments. The community’s preferred regeneration scenario has been developed through knowledge mobility and co-design workshops with the members of the community and a UCL team of designers and researchers. The WLCA of different regeneration scenarios (existing building, different refurbishment scenarios, and a previously approved redevelopment scheme) has been conducted using the data from desk-based research, site surveys, building regulations, retrofit case studies and guidelines, and the planning documents of the council’s previously approved new build scheme. The results of the WLCA support the current studies in favour of the refurbishment scenarios over the demolition and rebuilding of the estate, and make a case for the necessity of understanding the GWP in design development to reduce the GWP of regeneration scenarios.