Last week the UK government’s consultation on reforming Energy Performance Certificates (EPCs) in England and Wales closed. You’ve probably come across EPCs before when taking out a tenancy, buying a house or just browsing online platforms like Rightmove. The certificate explains how energy efficient a property is and how to improve it, using the same familiar colour coded A to G rating that we see on household appliances.

The government is making changes because there have been longstanding issues of accuracy, reliability, trustworthiness and a growing sense that EPCs are no longer fit for purpose.

At Nesta we’ve been thinking about EPC reform for some time. We think that an improved system can be an important enabler for our mission of substantially decarbonising home heating by 2030. Overall, we think the consultation includes a set of sensible and encouraging proposals, but we would advise that the Department look again at their approach to metrics - what EPCs measure - and ensure that adequate user testing informs the policy design. In this blog, we highlight some of the key points we made in our response.

A key change proposed in the consultation is a new set of metrics for assessing energy performance. Instead of the current rating - which relates to energy cost - the government is proposing four headline metrics:

1. energy cost
2. fabric performance
3. heating system
4. smart readiness.

While we agree with the government's objectives for metrics reform (providing more useful information to help users improve energy performance, reduce bills and decarbonise), we think that four headline metrics risks confusing users with too many variables and could lead to poor regulatory outcomes.

We think these metrics could be simplified to the two that we know users care most about: cost and carbon. We think these are the two issues that EPCs should communicate most clearly and be the main focus of recommendations to homeowners.

Users could be presented with the two different metrics on their EPC and shown two different user journeys: one for how they can decarbonise their heating system and the other for how they can reduce their energy bills. This dual metric would increase the prominence of the carbon rating (historically more of a technical detail) and present users with meaningful options and trade-offs for upgrading their home, with each metric showing a set of actions for improving the property’s rating. We highlighted what this could look like in a previous blog:

The same smart readiness metric is also referenced in a separate UK government consultation on minimum energy efficiency standards for the private rented sector in England and Wales. The proposal is for landlords to improve the energy efficiency of their properties so they meet a new standard, which is a combination of a fabric efficiency rating (upgrading insulation), and either improving a heating system metric (installing low-carbon heating) or improving a smart readiness metric (installing solar panels and batteries). We think that giving landlords this choice to focus on smart measures rather than decarbonising the heating system could be a missed opportunity for the sector, and risks leaving tenants with fossil fuel reliant heating systems - even as we expect the rest of the housing stock to upgrade to more efficient and low-carbon heating systems such as heat pumps.

User testing is often used to improve the design of existing tools or services, but it is more valuable to embed user needs and testing into the initial policy design. The government should be doing just that: undertaking more user testing upfront to inform the strategic direction underpinning reform.

Using the example of metrics, in order to achieve the government’s objectives of reform, it will very much depend on the user's behaviour - how people use the certificates and how they respond to the different metrics. We recommend that the government undertakes user testing before deciding on an exact approach on metrics to find out what information would be most persuasive to users and elicit action, before then defining the metrics that meet these desired outcomes.

You could, for example, imagine a metric that is technocratically designed “If we measure X, it will encourage homeowners to improve Y”. Despite best intentions, if users don’t value or understand it, or indeed misinterpret it, then it could fail to drive the action intended. By bringing more user testing into the design process itself, it’s then possible to embed that user experience into the strategic decisions.

We’ve had a think about how Nesta would approach this user testing

• Initially we’d want to do some use case mapping to understand the desired behaviours of different types of users. For example, you might expect a homeowner to take different actions to a prospective homeowner who’s looking to compare the likely energy bills of different properties.
• We’d then want to understand what information would be most persuasive to users, in different use cases, through qualitative/design research. This would inform which metric underpins the information shown to users.
• We’d then want to test each metric individually using a prototype design, and get qualitative feedback on whether it’s understood by users. This could be done on a broad range of outcomes at this stage - ie, whether a user is likely to take action as a result of a recommendation, whether they have a clear understanding of what a specific metric is or how to improve it.
• We’d then want to continue testing and iterating the design of the metrics and EPC certificate on specific outcomes to refine the design. This should lead to an optimised design that is centered on a good understanding of how different groups will actually use the certificates.

There are plenty of promising proposals in the consultation, and whilst the reforms have been long-awaited, elements such as metrics should not be rushed without proper testing. It’s vital to ensure EPCs lead to the outcomes that policymakers want.

Have you recently checked your EPC? You can look up yours here. How do you think the certificate could be improved?