The proposed changes to EPCs are doomed to fail

As fuel prices rocketed and net-zero commitments loomed, energy performance became a priority. According to online estate agent Rightmove, UK households are spending more than £9bn a year on wasted energy – money that could be spent more productively.

Knowing that it needs to do something, the government has announced a long-overdue reform of the EPC regime, the first serious attempt since its introduction. Getting it right could have a far-reaching impact on health, poverty and our environment.

The proposed changes to EPCs are a step forward, but they are no panacea. The consultation on EPC methodology prioritises things that will have little impact, and punts on straightforward changes that could be game changers.

“The key to better assumptions is having access to smart-meter data, or at the very least, the richer datasets that sit behind EPCs already, which are not publicly available”

First, the consultation suggests introducing multiple metrics (fabric performance, heating-system efficiency, smart readiness and energy cost). Fine – but most of these are already captured by EPCs today. While headline-grabbing studies flag error rates on EPCs of more than 60%, this includes technical errors such as uploading the EPC to the database twice.

Second, the consultation proposes replacing something called the Standard Assessment Procedure (SAP) with a new Home Energy Model (HEM), as well as more frequent updates, particularly for rental properties. This is welcome in principle.

The government already has a poor track record around this kind of modelling, and HEM doesn’t address the critical flaws. This sounds technical, but it matters, because if the models are wrong, all the legislation built upon them will fail.

The key to better assumptions is having access to smart-meter data, or at the very least, the richer datasets that sit behind EPCs already, which are not publicly available. The consultation makes vague reference to “exploring” integration with smart meters. We need this now.

Most EPCs are based on short, visual inspections. Domestic energy assessors can qualify after just five days of training. The average assessment costs £80 and takes around 15 minutes.

The result is sloppy data collection and fiddling with the numbers to qualify homes for grants (the reason basic measures like floor area are often wrong). Studies have found errors as high as ± eight points, enough to misclassify a home entirely. We need better training and higher professional standards to solve carelessness and corruption.

When the data is wrong, so are the decisions. Yet, there is one big thing left on the table: the UK’s 32 million smart meters. Access to smart-meter data could dramatically improve how we understand household energy performance.

The government says it will “explore” integration with smart-meter data, but that should be central, not optional. This is a missed opportunity to modernise not just the metric, but the measurement. The current excuse is that using the data would breach privacy rules set out under the General Data Protection Regulation – but that would not be true if it were anonymised.

“The government says it will ‘explore’ integration with smart-meter data, but that should be central, not optional. This is a missed opportunity”

So, how do we fix it?

An easy win would be to make sure we use the data we already have. At Domna, we work with housing providers to deliver smarter, data-driven retrofit planning. Our models draw on over four billion data points across 11 core datasets, including weather data, building records, Land Registry information and historical retrofit outcomes.

AI can help crunch data to better predict performance at the individual home level and validate results against actual usage using data science and machine-learning. Our approach is already delivering up to 97% accuracy, far ahead of traditional EPCs, based on real-world evaluation. Access to smart-meter data, or at least the datasets behind EPCs, would boost accuracy even further.

If we get this reform wrong, we risk misclassifying millions of homes, misdirecting public funds and delaying action on cold, inefficient housing.

However, if we get it right, EPCs could become a tool people trust, a foundation for investment, enforcement and meaningful change.

Anna Moore, chief executive, Domna