ESOS Phase 4 | Hot update!!!

The government has made changes to ESOS, which came into force on 22th July 2026 via the Energy Savings Opportunity Scheme (Amendment) Regulations 2026. The main changes are:

1. Removal of Display Energy Certificates (DECs) and Green Deal Assessments (GDAs) as compliance routes;
2. Progress against action plan commitments in Phase 3 to be included in the ESOS assessment;
3. Where action plan commitments have not been met, participants must provide an explanation.

In addition to the main changes, additional amendments have been made relating to:

• ISO 50001 participants;
• Supporting regulator and professional body functions and improving data quality.

Organisations which meet the qualification criteria on the qualification date for the fourth compliance period of ESOS (i.e. 31st December 2026) are required to comply with ESOS and these changes by 5th December 2027. The ESOS guidance explaining how to comply has been updated to reflect the changes. You can check if your organisation qualifies here.

More information about the changes to ESOS is set out below, with references to the relevant chapters of the ESOS guidance. For an illustrated comparison of differences between the Phase 3 and Phase 4 requirements, please see Annex A.

Phase 4 changes

I) Removal of DECs and GDAs as compliance routes and changes to ISO 50001 requirements – Chapters 7 – 9

These compliance routes have been removed as they are no longer considered to meet best practice standards. This means that from Phase 4 ESOS participants must use only energy audit(s) and / or ISO 50001 certification as compliance routes.

Participants with an ISO 50001 covering either the total energy consumption (TEC) or significant energy consumption (SEC) are exempt from:

• appointing a lead assessor (in Phase 3 this exemption only applied where ISO 50001 covered the whole of the TEC);
• completing an ESOS report (please note that this is NOT the energy audit report).

II) Progress against action plan commitments – Chapter 10.4.1

To meet this requirement, participants must provide additional details about the energy savings achieved during the compliance period. The details, which must be included in the ESOS report and notification of compliance (NOC) and which will not be published, are:

• A description of each measure implemented to achieve the energy saving;
• Energy savings achieved by each measure;
• Energy saving category of each measure (e.g. behaviour change, training, capital investment).

III) Action plan review – Chapter 10.5

If you were eligible to comply with ESOS in Phase 3, you were required to prepare and submit an action plan. You are now required to review your action plan as part of the ESOS assessment and the information provided in the ESOS report and NOC. The details required, which will not be published, are:

• Any measures proposed in the action plan and not implemented;
• Reasons why the measures were not implemented.

IV) Additional Phase 4 changes – Chapters 7, 11, 12 and Appendices A1 & A2 and Appendix B

• Lead assessors are now required to notify their professional body of each ESOS assessment they complete/review, along with the ESOS participant’s contact details. This is to allow the professional body to seek the ESOS participant’s consent to share its ESOS report so the professional body can carry out a quality check – see section 7.3 of Chapter 7
• The NOC must include the following – see Chapter 12 and Appendix B:
  • Total number of sites covered by energy audit(s) (voluntary in Phase 3)
  • ISO 50001 certification details (voluntary in Phase 3)
  • UK SIC codes only (replacing international codes in Phase 3).
• Improvements to recording of methods and data used for calculations – see Chapter 11 and Appendices A1 & A2.

We will provide further updates including details about the MESOS (Manage your ESOS) User Management in the next few weeks. Don’t hesitate to be in touch with us at info@esgsolutionsltd.com should you need more clarification about your energy and carbon legislative compliance.