Default data on EPC ratings – What it is, and how to avoid it

31st January, 2024

We sat down with Kieran Crowe, Director – Head of Net Zero Buildings at Low Carbon Alliance, to learn more about default data; the culprit that’s causing commercial property owners to spend millions on unnecessary work to increase the energy efficiency of their buildings.

Kieran Crowe
Kieran Crowe, Director, Low Carbon Alliance

Below, we’ve compiled Kieran’s comments regarding two of the most important areas — what default data is, and how to eliminate it. We’ve also included a case study example provided by Kieran, it focuses on how Low Carbon Alliance successfully removed a client’s default data, saving significant carbon emissions and money.

What is default data?

Every year, owners of commercial properties plan to spend millions on unnecessary work to increase the energy efficiency ratings of their buildings. The culprit is what’s referred to as ‘default data’.

As well as being responsible for unnecessary costs, it’s the reason behind an enormous number of carbon emissions incurred by avoidable building work. Quite an irony, considering its nefarious effects are associated with efforts to enhance green credentials.

It arises in the process of EPC certification assessment — an undertaking building owners are becoming intimately familiar with, as the 2030 deadline for all commercial buildings to hold a ‘B’ rating or better looms. EPC certifications are awarded via software which provides a rating to a building based on the data input into it via the building assessor. That data specifies to the software the building’s relevant physical attributes, for example how it is heated and insulated, the construction materials and thermal properties of its windows and floors, and more.

When some of that information is not available to the assessor, the software fills the blank fields automatically with what is referred to as ‘default data’.

It will judge the aspects of the building associated with those fields as negatively as possible, in order to give a conservative overall EPC rating. This usually means that the rating issued is much lower than the building should receive — and, as a result, often triggers significant building work to enhance it.

But if the correct data had been available, the rating might have been much higher. Therefore less building work, with its attendant costs and emissions, would be required. This is why avoiding the trap of default data, by finding the relevant information for your building, is so vital.

Unfortunately that information is usually disparate and spread across many stakeholders, meaning that this is often easier said than done.

Can default data be eliminated?

Unwarranted low scores and unneeded expenditure can be avoided with Low Carbon Alliance’s iEPC (TM) — an intelligent EPC testing service.

At Low Carbon Alliance, we specialise in providing clients with iEPCsTM (intelligent EPCs), which more accurately reflect the real energy efficiency of the building. With this information, we can recommend the most cost-effective methods of raising the score. The way we do so starts with the BRUKL report, a printout which shows the precise data used to calculate the current EPC score (we’ve seen BRUKL reports use as much as 90% default data). Once we know exactly which aspects of the building were evaluated using default data, we go to work to find the real information.

We start by creating a digital twin. This is a 3D graphical representation of the building, which we colour code to display where real data was used and where default data was relied on. We then age the building and begin researching its history. Building regulations of the period — which would have dictated minimum levels of performance for the windows, walls, etc — can be placed into the digital twin as assumed data. This is already an improvement on default data, but isn’t as accurate as it could be.

The next step is to speak to organisations involved in the building’s design and construction — architects, structural engineers, interior design companies and others — to discover if they have records of the property. (Sometimes the right data comes from unexpected places. Just recently I spoke to a manufacturer in America, hoping to get information on a twenty-year-old piece of machinery. They were able to help, and the impact it made on the EPC score was enormous).

All the data we collect is added to the digital twin, allowing our client to see clearly its precise impact on the EPC score. We can then advise on the most cost-effective changes to improve the score further — vital for both budgets and energy. 

Case study example: Brennan House

Previously, Low Carbon Alliance was employed to work on a 30,000+ square foot office building to improve their EPC rating to A — achieved primarily by avoiding the use of dreaded ‘default data’.

For Brennan House, an office building in Farnborough, built in 2004, the landlord felt the building’s EPC rating had room for improvement, both in terms of energy efficiency and in appeal to potential tenants, and asked our team to help.

We began by reviewing the pre-existing EPC assessment of the building, which revealed that a considerable amount of data regarding the building’s physical attributes had been left as ‘default data’. Our team then created a digital twin and performed the detective work to discover as much accurate data as possible regarding the building, including air conditioning (VRF), gas boiler, hot water heater, and specific details of the lighting, including light fittings.

A new assessment of the building was then conducted, incorporating this researched, accurate data. The result? A new EPC rating of ‘A’! This was particularly impressive when considering that the building uses gas heating for some of the core areas, and there was no need for costly and unnecessary renovations.

Our teams’ thorough research to avoid the use of default data provided value, both in terms of the improved EPC rating and the cost avoidance of superfluous building works.

Is your EPC rating where you want it? Ask Low Carbon Alliance about our ‘iEPC’, or intelligent EPC assessments.