The Scottish Government has confirmed that it will replace the Standard Assessment Procedure (SAP) with the UK Home Energy Model (HEM) calculation methodology, alongside a new EPC Register, as part of its response to the 2023 Energy Performance Certificate Reform Consultation, published in January 20251. Revised EPC regulations will be laid in the Scottish Parliament during 2025, with an intention to bring them into force in 20261.
The government said the new technical infrastructure would sit alongside a reformed rating system. It stated:
"establishing a new technical infrastructure to replace the current Standard Assessment Procedure (SAP) with the new UK Home Energy Model (HEM) calculation methodology, together with a new EPC Register"
The response also confirms a reduction in the validity period of EPCs from 10 to five years, and a new set of domestic ratings. These include a Heat Retention Rating on an A-G scale, a Heating System Type Rating showing the current and potential emissions category of the main heating system, thermal efficiency and running costs, and an Energy Cost Rating based on the cost of energy to run the home to standardised conditions1. The government said around 80% of homes currently in cost-based EPC EER band C also achieve band C in the new Heat Retention Rating1. The Heat Retention Rating bands are set out as follows1:
| Rating | Score | Description |
|---|---|---|
| A | 30 or less | High level of energy efficiency |
| B | 31 to 70 | High level of energy efficiency |
| C | 71 to 120 | Good level of energy efficiency |
| D | 121 to 215 | Lower level of energy efficiency |
| E | 215 to 301 | Lower level of energy efficiency |
| F | 302 to 350 | Lower level of energy efficiency |
| G | 351 or more | Lower level of energy efficiency |
The government said over 200,000 EPCs are issued every year in Scotland1. It also said it will shortly issue an additional technical consultation on proposed changes to EPC lodgement fees, which have not been revised since 20171. On alignment with EU rules, the response notes that the EU adopted the recast Energy Performance of Buildings Directive in April 2024, and that the Scottish proposals would already broadly align with its provisions1.
Why it matters for households
An EPC is the document a buyer or tenant sees when a property changes hands, and it is the basis on which fabric efficiency, heating emissions and running costs are described. Replacing SAP with the Home Energy Model changes how those figures are calculated, and a new Register changes where the certificate and its underlying data sit. The reduction in validity from 10 years to five means a certificate issued under the current system will date faster, and a home's stated performance may be reassessed sooner than under present rules. The addition of a separate Heat Retention Rating means insulation performance is reported distinctly from heating system performance and from modelled running costs, so a home's fabric and its heating are no longer collapsed into a single headline number. The government has said the Energy Cost Rating will be in line with the current Energy Efficiency Rating or SAP Rating1.
What happens next
Revised EPC regulations are to be laid in Parliament during 2025, with an intention to bring them into force in 20261. The government said it anticipates regulations coming into force in the second half of 2026, and that they will come into force for Approved Organisations and assessors at that point1. A further technical consultation on EPC lodgement fees is to be issued1. The response states that the Scottish Government is still considering its response to the related consultations on a Heat in Buildings Bill and a Social Housing Net Zero Standard, and will set out its position separately1.