• Energy Research

In the upcoming years, as the population is growing and ageing, as lifestyle changes create the need for more water and as fewer people live in each household, the UK water sector will have to deal with challenges in the provision of adequate water services. Unless critical action is taken, every area in the UK may face a supply-demand gap by the 2080s. Extreme weather events and variations that alter drought and flood frequency add to these pressures and there is therefore a need to develop evidence-based drought scenarios models for water management purposes. However, little evidence is available about householders’ response to drought and there are few if any studies that have synthesised this evidence. In response, this paper discusses the current empirical literature on the factors driving domestic water consumption under both ‘normal’ and drought conditions. The paper identifies the limited availability of evidence on the many different and evolving factors affecting domestic consumption under both ‘normal’ and drought conditions and stresses the need for the inclusion of inter and intra household factors as well as water use practices in future demand forecasting models. The paper then presents ‘Water Cultures’ as an integrative modelling framework to combine the limited evidence that is available on the interactions of social norms, practices and material cultures. This enables the paper both to capture both the uncertainty and heterogeneity of individual and/or household level variation and also outline the research gaps that need to be addressed.

This analysis compares the difference between the Energy Performance Certificate (EPC)-modelled and smart-meter measured annual energy use on a like-for-like basis in 1,374 gas-heated British households from the Smart Energy Research Lab (SERL) Observatory. EPCs and metered energy use were converted to primary energy use intensity (PEUI) to provide a comparison of the same quantity for the first time.We show that EPCs predict significantly more energy use than metered in homes in Great Britain. EPC bands A and B show no statistically significant difference, but all other bands show a significant gap which increases as EPC rating worsens. The PEUI gap widens from -26 kWh/yr/m2 (-8%) for band C to -276 kWh/y/m2 (-48%) for bands F and G. Unlike previous research, we show that the difference persists in homes matching the EPC-model assumptions regarding occupancy, thermostat set-point and whole-home heating; suggesting that occupant behaviour is unlikely to fully explain the discrepancy. EPCs are a core tool in the residential energy sector, and the gap between EPC-modelled and metered energy use could have a significant impact on policy, research, and industry. Future research should investigate disaggregated components of energy use, the underlying thermal model, and assumptions regarding building characteristics.