Which? published its response to the Department for Energy Security and Net Zero (DESNZ) consultation on the Home Energy Model for Energy Performance Certificates on 23 March 20261. The consumer body said it welcomed the government's plans to reform EPCs, and set out concerns about the accuracy and reliability of assessments and about how long a certificate stays valid1.
The response states that EPCs "have the potential to be a valuable tool for consumers wanting to understand the energy efficiency of their home or a property for sale or rent, and a gateway for understanding the improvements consumers can make to their home"1. Which? adds that EPCs "also have an important role in demonstrating compliance with minimum energy efficiency standards for rented homes and eligibility for some forms of finance"1. It links these points to the government's Warm Homes Plan and to ongoing concerns about energy bills1.
On the current system, Which? says its research has found "limited consumer engagement with EPCs, poor understanding of the current metric, and recommendations that are not seen as relevant or useful"1. Its investigations, it says, "have also highlighted serious issues with the accuracy and reliability of EPC assessments which we expect the government to address in future reforms"1.
The validity period is a specific point of disagreement. Which? states:
"The government's decision to maintain the 10 year validity period for EPCs will also undermine accuracy as data will inevitably become out of date in that period."
On the Home Energy Model itself, Which? says most consumers will not engage with the detailed points, but that it is important the metrics accurately reflect relevant aspects of the property and its heating and hot water system, and can be easily explained to consumers1. It adds that where consumers do want to engage with the detailed data behind the ratings, this should be supported1. The full response is available as a PDF of 210 KB1.
Why it matters for households
An EPC is the document a householder meets when buying, selling or renting a home, and it is also the evidence used for minimum energy efficiency standards in the rented sector and for eligibility for some forms of finance1. If the rating rests on data that has aged, the certificate a household relies on may not describe the property as it now stands. Which? states that the 10 year validity period will undermine accuracy for that reason1.
The Home Energy Model is the replacement for the calculation method behind EPCs, so the metrics it produces determine what a rating means in practice and what improvement measures are suggested. Which? says recommendations under the current system are not seen as relevant or useful, and that understanding of the current metric is poor1. For a household weighing up work on a home, the practical question is whether the certificate and its recommendations reflect the building and its heating and hot water system accurately1.
What happens next
The response was submitted to the DESNZ consultation on the Home Energy Model for EPCs1. No outcome, timetable or government response to the consultation is reported in the published response1.