Renovate or replace? Consequential replacement LCA framework for buildings

Abstract

Is it more environmentally friendly to replace an existing building with a new one or to renovate the existing property? This paper addresses how to frame and evaluate this question. Although several previous studies exist, their methods lack a harmonised set of practice. A new framework is introduced that adopts the concept of consequential replacement framework (CRF) for life cycle assessment (LCA) which had previously been applied to vehicles. The application of the CRF to buildings is demonstrated with case studies on school buildings in Finland. Three alternative cases are examined: the refurbishment of a 1950s school; extending it with an annex; and demolition and replacement with a new concrete or timber building. As the European environmental impact regulation of buildings pertains to CO 2 emissions, the paper also focuses on CO 2 . The case studies demonstrate that refurbishment in Finland is a more climate-friendly alternative to demolition and new build. The studied new buildings’ better energy efficiency is set off for decades by the carbon spike caused by the embodied CO 2 in their materials. The CRF is shown to be a methodologically sound, easily approachable framework for evaluating immediate environmental consequences of decision-makers’ retention or replacement choices, suitable to different contexts.