Headline EPC band grades in Scotland and England should not be directly compared because of the different calculation bases that are been used to generate a result. The different calculation methodology used in Scotland and the rest of the UK is at first glance misleading. The different systems have led to confusion as the grades achieved may appear very different.
To compare the energy efficiency of buildings in England and Scotland more information needs to be considered than just the headline rating achieved.
Often ratings in Scotland appear to be poorer than a similar building would achieve and this cannot be attributed to weather factors. A building in England will appear to be more energy efficient than that same building in Scotland and this may cause investors to favour investment bias towards England.
Case study
By way of background, the calculation engine behind non-domestic EPCs is SBEM.
As a basic example of the different rating an English and Scottish EPC can give we compared the rating of an actual EPC for a standalone modular retail unit we recently carried out an EPC for (2014). The unit benefits from a new high efficiency split system (utilising air source heat pump technology) and T5 lighting. All specific building and efficiency data is available including the actual air infiltration rate based on an actual air pressure test result, lighting is from actual design data, actual specific fan power for supply air and DHW from heat losses.
The calculation was run with the building location being in Scotland and then England. As above the calculation method will be different and the results are as follows.
Region Rating
Scotland C 44
England B 26
Looking closer
If the energy efficiency grade of the buildings were compared it would appear that the English building was far more energy efficient than the Scottish building. This is not the case however. If the BER of the English EPC (located at the foot of the first page) was compared then the comparison would be more representative.
Further consideration
While the England & Wales approach, based on a self-reference scale, tends to return wide band ranges for wide energy performance ranges, the Scottish approach, based on absolute carbon and the current limits within the bands, produces a reduced range of bands for wide performance ranges in certain sectors
English and Scottish minimum regulations
In addition to differences in ratings calculation systems in England and Wales it is important to note that there are different ‘minimum energy efficiency regulations’ for England / Wales and Scotland.
