Climate change mitigation potential in building preservation: comparing the CO2 performance of four refurbishment alternatives to new construction

Abstract

ABSTRACT Older buildings are often vilified for alleged poor energy performance. This discussion has, however, been limited to operational energy, rather than whole-life carbon. This paper compares both embodied and operational carbon emissions of building preservation to new construction. Methodologically, it relies on consequential replacement LCA. Using a representative 1950s school building as a case study, a locally heritage-listed example of Modernist architecture, four retention scenarios are devised. The scenarios represent different approaches towards repair needs, cost implications, time horizons of refurbishment, and conserving the building's architectural-historical value. For the contemporary new build, two scenarios are developed based on a case study school building completed in 2018. They differ by the material of the structural frame (concrete or cross-laminated timber). The concrete-framed alternative corresponds to the present business as usual, whereas the wooden alternative represents a competing lower-carbon technology. The study was conducted in Finland, i.e. a cold continental climate. In such conditions, operational energy consumption is significant for a building's carbon footprint. Nevertheless, the findings show that building preservation results in lower emissions than new construction in most of the scenarios. The climate change mitigation potential of building preservation is significant at the scale of singular buildings and the building stock scale.