Comparative environmental assessment of heat pumps and gas boilers under evolving electricity mixes and climate change: A Case Study of a Residential Building in London

This study compares the environmental performance of 18 impacts of a timber structured residential building in London, when heating and DHW are either provided by a heat pump or a condensing gas boiler by considering the dynamic effects of climate change and electricity mix evolution. A Life Cycle Assessment (LCA) approach was followed. To accurately describe future electricity mixes relevant for embodied and operational modules, the Life Cycle Inventory (LCI) was modified reflecting future projections for the UK, EU and China. The influence of climate change was considered through dynamic thermal simulations using London’s future climatic projections. Results show a general reducing trend in the building’s heating demand driving the overall energy needs of module B6 of EN15978 down. Switching to a heat pump makes the building perform significantly better in terms of lifecycle carbon, land transformation and fossil depletion benefiting from grid decarbonisation. However, the pressure on several beyond carbon impacts such as ozone depletion, ecotoxicity, eutrophication and metal depletion intensifies. This highlights the need for a holistic approach when switching technologies towards Net Zero to avoid trade-offs. As most beyond carbon impacts that expect intensified pressure are geographically specific, future research is needed to examine whether more granular data will corroborate this study’s trends. This is to help assess whether the pressure on beyond carbon impacts is of concerning magnitude. Finally, although the installation of active cooling devices was not considered for comparability consistency, results show cooling demand might become important in future.