Fuel poverty-induced ‘prebound effect’ in achieving the anticipated carbon savings from social housing retrofit

Social housing retrofit is often seen as a way to contribute to carbon reductions as it typically encompasses large-scale interventions managed by one landlord. This work investigates the carbon savings potential of a deep retrofit in a local authority owned 107-flat tower block, taking into account the tenants' pre-retrofit heating strategies. Prior to the retrofit, temperature and relative humidity monitoring were undertaken in 18 flats for 35 days. The measurements were then used to develop occupant heating profiles in the 18 homes. Dynamic thermal simulation of the flats pre- and post-retrofit using the identified user heating profiles highlights that for these fuel poverty-constrained flats, the estimated carbon savings of retrofit will be typically half those predicted using standard rules for temperatures in living spaces. Practical application: The findings presented in this paper demonstrate the impact of fuel poverty on the expected benefits from social housing retrofit schemes, providing information relevant to multiple stakeholders: (1) building industry: The study highlights the need to use empirical data in building energy modelling, as typical conditions could be far from representative in social homes (2) Policy makers and social landlords: Targets for CO2 reduction may not be achieved through retrofitting, but the social impact could be much greater and more critical than assumed. The findings under this work help to direct incentives for retrofit schemes towards the social and health benefits achieved.