KJ Tait

MEES EPC ‘B’ Standard – Accelerating Decarbonisation

8 August 2022

When the Minimum Energy Efficiency Standards (MEES) were introduced in 2015, there was little to no risk for our Clients in achieving the minimum standard of an ‘E’ rated EPC, perhaps with the exception of stripped back shop units. If an EPC was below this standard, they could be confident that a reassessment from an experienced M&E Consultant led EPC Assessor or small capital investment could get them to the required standard.


With the expected strengthening of minimum level of EPC to ‘B’ by 2030 combined with the changing carbon factors in Part L 2021, we are seeing change that is accelerating decarbonisation in the built environment. Why is this? Traditionally, it has been possible to achieve a ‘B’ rated EPC with gas boilers, however, the reduction in carbon emissions from Part L 2021 for grid electricity is now seriously affecting this. This is due to the methodology being a comparison between what’s termed the ‘Reference Building’ and the ‘Actual Building’. The ratio between the two buildings is multiplied by 50 to then give the Asset Rating. For example, if the Actual Building has the same carbon emissions as the Reference Building, then the Actual Building would achieve a ‘B’ rated EPC of 50 Asset Rating points.


The Reference Building is always heated by gas but crucially the lighting systems are poor. This means that the carbon emissions in the Reference Building are reducing significantly with the change and hence the ratio between the two buildings is likely to reduce.


The change in carbon factors has been long overdue. Whether making it harder for gas heated buildings to achieve a ‘B’ was foreseen or not, it will help to remove these systems from buildings quicker than if the carbon factors remained at Part L 2013 levels. The expected need to be at the ‘B’ level by 2030 is driving change with 10 year plans now being put in place that look into replacing gas fired boilers with lower carbon alternatives.