Comparative cost analysis of traditional and industrialised deep retrofit scenarios for a residential building

Abstract

In this paper, the economic competitiveness for deep retrofit actions between the industrialised off-site and the traditional on-site approaches are discussed by using a comparative Life Cycle Costing (LCC) analysis. This assessment was based on a deep analysis of all renovation-related cost and timing processes, from design to operation and maintenance phases. The study was based on three retrofit scenarios for an existing building in Italy undergoing a deep renovation. The Life Cycle Inventory (LCI) was developed starting from real costs and a list of bills collected by the design team and the industrialised technologies developers. Afterwards, the LCC modelling was performed for all scenarios. The results show that the two deep retrofit approaches (traditional and industrialised) are comparable in terms of investment costs, even if a gap of around -7% and +16% still exists. This highlights a potential for technological optimisation. Moreover, the operation and maintenance phase has shown to be key to transforming the expected higher quality of the industrialised components into a prolonged life expectance, hence highly impacting the whole cumulated Net Present Value. Finally, the analysis of the End of Life (EoL) phase in case of possible reusing of some dismantled components in the industrialised scenario resulted in contributing in a relevant way to increase the final value of such an approach.