C16 -- Whole-Life Carbon Assessment & Cost Analysis for the Renovation of Social Housing Buildings in Ireland

This paper tackles the issue of the whole-life cycle decarbonization of multi-family social housing buildings undergoing a renovation process. Focus is placed on a study realized in collaboration with the Dublin City Council, in order to understand the impact on greenhouse gas emissions, and costs, associated with the renovation of a multi-family building located in Dublin (Ireland), inclusive of a total of 23 apartments. Four different scenarios were analyzed, ranging from shallow retrofit options up to the full rebuild of the building from its core and shell structure. These four renovation options were compared in terms of whole-life cycle greenhouse gas emissions, as well as costs, and at various lifecycle stages (over 10, 30 and 60 years).

A baseline energy model of the building was created and validated against energy consumption figures from similar reference buildings and, where available, energy bills from the actual units. The integration between the Virtual Environment (VE) and OneClickLCA software was then used to calculate the embodied carbon associated with each scenario together with the operational carbon associated with the use of the building over its lifetime. The study identifies a deep retrofit as being the best approach to minimize lifetime carbon for this building, outperforming even the full rebuild due to the high upfront carbon emissions associated with the demolition process and the need for new materials. As expected, the deep retrofit outperforms the full rebuild scenario in economic terms as well, with an approximate 50% lower upfront investment.

The science-based approach facilitated the decision-making process and potential future studies might be pursued to scale the assessment across multiple social housing units within Dublin and Ireland and provide a quicker route to the decarbonization of Dublin city.