City-wide Building Energy Efficiency Assessment Using EPC Data

The UK EPC scheme was established in 2007 as a response to the European Union Directive 2002/91/EC (Council of the European Union 2002), which aims to promote improvements on building energy efficiency and requires member states to develop their own scheme of evaluating and labelling the energy performance of buildings (UK Government 2007; Department for Communities and Local Government 2014b). The UK EPC scheme requires dwellings (both domestic and commercial) to have an Energy Performance Certificate (EPC) when constructed, sold or let (Department for Communities and Local Government 2014a). Each of the certificates presents energy system information of an individual dwelling and gives a rating (from G to A+) to indicate the overall energy efficiency of the dwelling as a whole. In addition, the certificate also shows efficiency ratings of building elements and provides recommendation of measures that can be undertaken to improve the dwelling’s energy performance. The recommendations of an EPC includes an economic assessment to make clear to the building owner the impact of any energy saving potential of the recommended interventions and their indicative cost. By April 2014 around 11.2 million EPC have been completed for UK dwellings, which is equivalent to 44.8% of the total number of households (DECC 2014). During the 12 month period ending June 2015, over 2 million EPCs were lodged into the database (Department for Communities and Local Government 2015) and all existing datasets can be requested to review by the public. Such database provides in-depth knowledge about the energy usage efficiency within individual buildings, and the high coverage of such data enables high-resolution building energy studies to be conducted at a city scale. Using the widely-acknowledged classification method by Swan & Ugursal (2009) in which energy modelling approaches are separated into two different categories – top down and bottom up, Johansson et al. (2016) pointed out that EPC data have the potential of supporting both bottom-up and top-down approaches. Their argument is supported by the work of Fabbri et al. (2012), in which city-wide EPC database was integrated with tools from the geographic information systems (GIS) for the analysis of energy performance of a city in Italy. Similar approach has also been Wu, Y, et al. 2018 City-wide Building Energy Efficiency Assessment Using EPC Data. Future Cities and Environment, 4(1): 3, pp. 1–7, DOI: https://doi.org/10.5334/fce.10