ESOS guidance

This page is a starting point for the ESOS cluster.

For the full step-by-step walkthrough of qualification, energy audits, action plans and notification, see the ESOS compliance guide — the complete reference for how to comply.

The audit itself is covered in our ESOS energy audit requirements guide, with ISO 50001 certification available as an alternative compliance route.

The Energy Savings Opportunity Scheme operates under the Energy Savings Opportunity Scheme Regulations 2014, as amended by SI 2023/1182 and SI 2026/701, and is administered by the Environment Agency.

Phase 4 qualification is assessed at 31 December 2026, with a compliance deadline of 5 December 2027.

Organisations that miss this deadline face civil sanctions — our ESOS penalties and enforcement guide sets out the maximum fines and how the Environment Agency applies them.

The Environment Agency published the ESOS Phase 4 guidance on 30 July 2026, implementing SI 2026/701, which came into force on 22 July 2026.

It removes Display Energy Certificates and Green Deal Assessments as compliance routes, and adds three duties: reporting the energy savings actually achieved, a review of measures from the previous action plan that were not implemented, and a third progress update on 5 December 2031.

Phase 3 participants owe their second action plan progress update by 5 December 2026.

For a full rundown of what changed for Phase 4 compared with the previous compliance cycle, see our ESOS Phase 3 vs Phase 4 guide.