Energy Systems Catapult published a report on 13 December 2023 finding that the metrics, methodology and uses of domestic Energy Performance Certificates should be reformed. The report, Making Energy Performance Certificates Work for Net Zero, says the current system is not aligned with the decisions needed to cut building emissions and widen access to warm homes1.
The Catapult identifies three issues: a gap between actual energy consumption and the consumption modelled by EPCs, inconsistency between ratings given by different Domestic Energy Assessors for the same property, and a bias towards intensive gas heating over low carbon technologies such as air source heat pumps, which it attributes to the focus on energy costs in the current Energy Efficiency rating1. It also says the system treats each property individually, with little consideration of local context, limiting whole system planning1.
The report puts a cost on continued gas boiler recommendations. Taking only the houses sold each year, it says that if EPCs continue to recommend new gas boilers at the current rate of 25 per cent of cases until 2035, the total societal cost of the resulting excess carbon emissions would be between £19bn and £57bn in the period up to 2050, compared with a scenario where an efficient low carbon heating technology such as an air source heat pump were installed1.
The proposed replacement is a set of three equally significant metrics rather than a single headline rating1:
| Metric | What it would indicate |
|---|---|
| Energy Use Metric | Predicted total energy use of the fixed elements of the building, incentivising both fabric efficiency and heating system efficiency |
| Climate Impact Metric | Emissions attributable to the property's energy use |
| Energy Cost Metric | How the property's energy costs compare to others |
The Catapult says policy uses should be matched to the relevant metric, with fuel poverty policy using the energy cost metric and Net Zero policy focusing on the climate impact metric1. It also proposes a Smart Building Rating to indicate a building's capacity to provide flexibility to the electricity system, and Digital Building Passports bringing together information about a building's energy performance to support integration with Local Area Energy Planning and personalised retrofit advice1.
"EPCs, in their current form, are undermining efforts to achieve Net Zero. Our recommendations recognise the central role that EPCs play in the property market, and in policymaking to create the conditions necessary for innovative solutions to home decarbonisation to flourish."
Why it matters for households
An EPC is required when a home is bought, sold or rented in England, Wales and Northern Ireland, and the Catapult notes the rating is ingrained into how property changes hands in those nations1. Because the current rating leans on energy costs, it can favour gas heating over low carbon alternatives, so the certificate a household receives may point away from the technologies that cut emissions1. The report also says ratings for the same property can differ between assessors, which matters where a rating is used as a condition of a tenancy, a grant or a mortgage1. The proposed energy cost metric would keep a cost comparison in the certificate, while a separate climate impact metric would carry the emissions signal, so the two purposes would no longer sit on one number1. Digital Building Passports, as described, would hold a building's performance information in one place, which the Catapult links to personalised retrofit advice1. The report does not set out how any of this would be delivered, funded or enforced, and no government response or timetable is reported1.
What happens next
No next steps, consultation dates or implementation timetable are reported1.
Sources1 cited
- EPCs undermining decarbonisation efforts | ESC report, es.catapult.org.uk