UK EPC data on existing buildings
Bearing in mind that some of the measures and properties outlined in the HEED data may yet to show up in the EPC records. We can consider that there may be a further number of dwellings whose improvement measures may have been undertaken by occupant and would not appear in the HEED data set either. This further highlights the difficulty in getting representative figures for retrofit measures in the UK.
Acknowledging these limitations in the data we can estimate the number of deep retrofits undertaken in the UK from the EER data, by subtracting the data on new builds (DECC, 2015c) from all EER EPC data (DECC, 2015a). Given that an EPC certificate is valid for 10 years, it can be assumed that each EPC will represent a unique property, or one that has undergone retrofit measures, to require a new EPC to be produced. We can see from Figure 1 that has been no observable trend in the number of A and B rated EERs since the introduction of EPCs in 2008.
Figure 1 Annual number of non-new build EPCs with EER ‘B’ or higher rating in England and Wales (DECC, 2015c, DECC, 2015a)
As shown from Figure 1 it can be argued that the range of government energy efficiency schemes have had little impact in increasing the energy performance to the benchmarks defined as ‘Deep retrofit’ or EER ‘B’. The data indicates a cumulative total of 438,469; or 3% of all non-new build EPCs at or above this banding.
It is important to consider that this data may include some new build/ un-modified properties built to EER B rating and above prior to the introduction of the EPC standards in 2008. This is most likely in more recent properties between 2002 and 2008, once the SAP and TER requirements had been introduced.
However when we look into those properties that have achieved an A rating only, a more observable upward trend can be observed, (Figure 2.)
Figure 2 Annual numbers of EPCS with EER ‘A’ rating in England and Wales DECC (DECC, 2015a)
The trend is also more clearly observed in the records for the EIR metric shown in Figure 3
Figure 3 Annual numbers of EPCS with EIR ‘A’ rating in England and Wales DECC (DECC, 2015b)
This may be reflective of the increased number of buildings refurbished to high voluntary or local authority mandated standards such as BREEAM Domestic refurbishment. The likely contribution of these standards to the EPC data is explored later in this series. The impact of solar PV installations on these figures will also be discussed later on in the series.
DECC 2015a. D1 – All Dwellings in England & Wales – Number of Energy Performance Certificates lodged on the Register by Energy Efficiency Rating – in each Year/Quarter to 30/06/2015. London: Department of Energy and Climate Change.
DECC 2015b. D2 – All Dwellings in England & Wales – Number of Energy Performance Certificates lodged on the Register by Environmental Impact Rating – in each Year/Quarter to 31/03/2015. Department of Energy and Climate Change.
DECC 2015c. NB1 – Number of New Dwelling Energy Performance Certificates lodged on the Register in England & Wales by Energy Efficiency Rating – in each Year/Quarter to 30/06/2015. London: Department of Energy and Climate Change.