Energy Performance of Buildings Certificates

Overview

At the time of this report, the Energy Performance of Buildings Certificates statistics are published as official statistics by the Ministry of Housing, Communities and Local Government (MHCLG).

The statistics provide information about energy certificates for buildings in England and Wales. They include figures concerning two types of certificates in the Energy Performance of Buildings Register: Energy Performance Certificates (EPCs – issued for domestic and non-domestic properties); and Display Energy Certificates (DECs – issued for buildings occupied by public authorities).

This report presents the findings and recommendations from our review of whether the statistics meet the standards of Trustworthiness, Quality and Value set out in the Code of Practice for Statistics (the Code).

Why we did this review

These statistics are the only official statistics on EPCs produced in the UK and have high-profile uses. For example, the statistics are used to produce estimates of net additional dwellings in MHCLG’s accredited official statistics ‘Housing supply: indicators of new supply, England’, which in turn are used to assess progress towards the UK Government’s aim of building 1.5 million homes in England.

In October 2024, MHCLG changed the status of these statistics from ‘official statistics in development’ to ‘official statistics’. We agreed with MHCLG to undertake a review when the statistics were no longer labelled as ‘in development’. The purpose of our review was to understand how the statistics had been developed in relation to the Code, and to provide recommendations for their further development, particularly given their increased profile and use.

Findings

The data source, methodology and quality assurance process are all suitable and are clearly explained in the bulletin and technical notes. The statistics team promotes a good quality culture by having regular meetings with the other teams involved in the quality assurance process. The team present relevant and important limitations of the data, and caveats are stated throughout the outputs. The ‘How the data should be used’ section of the bulletin is a particularly strong example.

Tentative policy changes will likely affect the statistics (for example, updated EPC metrics). The team has engaged with key policy stakeholders about these changes to represent the needs of EPC statistics users. The team also told us that it is planning comprehensive user engagement to inform any changes to its outputs and is carefully considering how it will communicate such changes. The team has previously undertaken and published user research, and produced change notes to inform users of developments in the statistics.

The bulletin tends to report rounded figures, while the accompanying live tables and interactive dashboard present unrounded figures. The reason for presenting rounded figures was not initially explained in the bulletin, but the team added detail about the use of rounding following feedback highlighted during our review. However, there is little explanation of uncertainty or the fact that rounded figures are approximate (for example, using qualifiers such as ‘approximately’ or ‘about’ alongside rounded figures).

The bulletin provides links to related statistics from across the four UK nations. However, no information is presented about the comparability of the figures across the four nations (for instance, relevant policy differences between England and Wales), nor potential implications when making such comparisons.

Time series of the percentages of energy efficiency ratings for existing and new domestic dwellings are clearly presented in stacked bar charts, although other graphs only present data for the most recent quarter. MHCLG told us that time series for energy efficiency ratings were adopted in response to user feedback and were intended to increase value for users. We highlighted to MHCLG that the descriptions of the time series lacked clarity about the period of the data referenced, and whether the percentages relate to the whole year or just to the quarter. In the January to March 2026 bulletin, which MHCLG published during our review, the team clarified the period to which the data relate in the time series title and notes.

The accompanying interactive dashboard presents detailed information in an appropriately structured way, enabling users to explore the data easily. During our review, the landing page of the dashboard indicated that it had not been updated since the previous release, although the most recent figures were available in the live tables. MHCLG told us that this delay was due to inconsistencies that it had identified, although users were not informed about this issue. The team resolved the issue during our review, and the dashboard was updated on the same day as the publication of the most recent statistics.

MHCLG is in the process of implementing the updated Code of Practice for Statistics (Code 3.0), including the preparation of required organisational and policy documents. MHCLG will have published these documents by the end of August 2026, and has published an interim statistical work programme and policy statement.

Our judgement

We conclude that the official statistics ‘Energy Performance of Buildings Certificates’ meet the standards set out in the Code of Practice for Statistics. The statistics are presented clearly and impartially, with strong supporting documentation about quality to support user understanding. As these statistics are the first set of official statistics on EPCs in the UK, we were particularly impressed by the production and presentation of these outputs.

We recognise that significant policy changes are likely to happen soon, which will affect the EPC statistics. We commend the team’s early collaboration with relevant stakeholders and welcome its plans to ensure that the quality and value of these statistics are maintained while implementing these changes.

Based on the findings of our review, we recommend the following:

To be open about the quality of its statistics, MHCLG should review how it communicates uncertainty and presents rounded figures across the suite of EPC statistical outputs. OSR’s guidance on presenting uncertainty and dashboards might be useful when addressing this point. The team should also review the suitability of its rationale for rounding across its EPC outputs by gathering feedback through the user engagement it is currently planning.
To support users’ understanding of the statistics, MHCLG should add information about comparability across the four UK nations, and any relevant issues that might affect the interpretation or comparison of the figures for England and Wales.
MHCLG should consider whether there would be benefit to users in presenting more graphs as time series, in a similar way to the energy efficiency ratings for existing and new domestic dwellings stacked bar charts.
If changes to EPCs (for example, the introduction of new EPC metrics) result in new statistics being added to the bulletins, MHCLG should consider how to present and label such statistics (for example, adding an ‘in development’ section).
MHCLG should also ensure that it communicates any issues with the bulletins or wider outputs (for example, the dashboard) to users in a clear and timely manner.
MHCLG should continue to progress the production of organisational policy documents and statements in line with Code 3.0.

Next steps

We expect MHCLG to have implemented Code 3.0 by August 2026, and to provide a public update on its progress against our recommendations by the end of November 2026.

We will meet with the MHCLG team in early 2027 to discuss whether the forthcoming EPC policy changes that affect the official statistics have been implemented (such as updating EPC metrics), and how the team has responded to such changes.

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