Equas helps large UK organisations understand, manage and meet their Energy Savings Opportunity Scheme (ESOS) obligations. Our registered ESOS Lead Assessors can support your in-house team, review and sign off your assessment, or manage the entire compliance process on your behalf.
With the second Phase 3 annual progress update due by 5 December 2026 and the Phase 4 compliance deadline on 5 December 2027, now is the right time to confirm your position, organise the required evidence and plan the work ahead.
Not sure what your organisation needs? Speak to an ESOS consultant for an initial, no-obligation discussion.
How Equas can help with ESOS compliance
Our ESOS assessment support service is flexible. We can fill a specific gap in your internal capability or provide a fully outsourced service from initial scoping through to assessment, director approval and notification.
Depending on your position, we can help you with:
- determining whether your organisation or corporate group is likely to qualify for ESOS;
- preparing the second Phase 3 annual progress update due on 5 December 2026;
- reviewing your Phase 3 evidence, action plan and previous progress update;
- planning and completing your Phase 4 ESOS assessment;
- calculating total and significant energy consumption;
- auditing energy use across buildings, industrial processes and transport;
- undertaking compliance ESOS assessments;
- identifying practical, cost-effective energy-saving opportunities;
- preparing the ESOS report and evidence pack;
- registered ESOS Lead Assessor review and sign-off;
- board-level review and approval;
- completing the required notification through the government’s ESOS reporting system; and
- assessing whether ISO 50001 is an appropriate route for your organisation.
ESOS Phase 3 progress-update support
If your organisation qualified for ESOS Phase 3, it was required to submit an action plan and report progress against its commitments in the following two years.
The first annual progress-update deadline was 5 December 2025. The deadline for the second annual progress update is 5 December 2026. The update must be signed off by a board-level director or equivalent and submitted through the Manage your ESOS reporting service.
We can help you:
- review the commitments in your action plan;
- confirm which measures were implemented during the reporting period;
- calculate or estimate the resulting energy savings in kWh;
- explain changes to planned measures;
- assemble a clear audit trail for your evidence pack;
- prepare the information for director review; and
- support submission through the government reporting service.
Get help with your 2026 ESOS progress update
ESOS Phase 4 compliance support
Phase 4 covers the compliance period ending on 5 December 2027. Organisations that meet the large-undertaking criteria on the expected qualification date of 31 December 2026 will need to complete the relevant assessment and notification requirements by 5 December 2027.
Starting early gives you more time to gather reliable energy data, coordinate sites and group companies, secure a registered Lead Assessor and turn the audit findings into useful cost and carbon reductions.
The Energy Savings Opportunity Scheme (Amendment) Regulations 2026 introduced additional Phase 4 requirements. These include stronger reporting of energy savings achieved since the previous compliance deadline, a review of measures from the previous action plan, and a further annual progress update. Display Energy Certificates and Green Deal Assessments have also been removed as alternative compliance routes.
Detailed government Phase 4 guidance is still being developed. We will apply the legislation and the latest regulator guidance available when your assessment is completed.
Our outsourced ESOS assessment service
If you do not have the time or specialist resources to manage ESOS internally, we can coordinate the complete assessment process.
Our outsourced service can include:
Scope and qualification review. We establish the participating organisation or group structure, confirm the assessment boundary and identify the people and evidence required.
Energy data collection. We help collate energy consumption for buildings, industrial processes and transport over the relevant 12-month reference period.
Significant energy consumption assessment. We identify the areas that collectively account for at least 95% of total energy consumption and determine the appropriate audit coverage or recognised compliance route.
Energy audits and opportunities. Our consultants assess relevant operations and identify proportionate, practical measures to reduce energy use, cost and emissions.
ESOS report and evidence pack. We document the methodology, calculations, findings and supporting evidence required to demonstrate compliance.
Lead Assessor review. A registered ESOS Lead Assessor reviews the assessment and confirms that it meets the applicable requirements.
Director approval and notification support. We prepare the information for board-level sign-off and support your notification through the government reporting service.
Discuss a fully outsourced ESOS assessment
Registered ESOS Lead Assessor review and sign-off
If your team is completing the assessment internally, our registered ESOS Lead Assessors can provide independent review, guidance and formal sign-off.
We can become involved early to confirm that your proposed scope, energy data and audit approach are suitable. This reduces the risk of discovering gaps shortly before the compliance deadline.
Our Lead Assessor support can include:
- reviewing organisational and group boundaries;
- facilitating disaggregation of group reporting where that is beneficial;
- checking total and significant energy consumption calculations;
- reviewing audit coverage, methodology and findings;
- identifying gaps in the evidence pack;
- confirming that required information is presented clearly;
- supporting the responsible officer’s review; and
- completing the Lead Assessor approval required for notification.
Speak to a registered ESOS Lead Assessor
Independent ESOS advice
Some organisations need strategic advice before committing to a particular compliance route. We can review your current arrangements and recommend a practical way forward based on your estate, operations, internal resources and existing management systems.
This can help you decide:
- whether to manage the assessment internally or outsource it;
- where specialist energy audits are required;
- how to coordinate compliance across a corporate group;
- how to strengthen energy-data collection before Phase 4;
- how to connect ESOS recommendations with operational and carbon-reduction plans; and
- whether ISO 50001 would provide wider long-term value.
Following the review, you will receive a clear scope of work and a fixed-price proposal for any further support.
ISO 50001 as an ESOS compliance route
A certified ISO 50001 energy management system can provide a route to deemed compliance with certain ESOS assessment requirements.
Under the regulations now in force for Phase 4, an organisation can be deemed to have complied with the duties to appoint a Lead Assessor, conduct an ESOS audit and produce an ESOS report where its total energy consumption (or the significant energy consumption representing at least 95% of its total) is covered by the certified energy management system.
Where ISO 50001 covers only part of the organisation’s energy consumption, the remaining consumption may still need to be addressed through the ESOS assessment process.
We can assess whether ISO 50001 is a proportionate option and, where appropriate, help you design and implement an energy management system through our ISO 50001 consultancy service.
Why you should choose Equas as your ESOS consultant
- Registered ESOS Lead Assessors: specialist review and sign-off from appropriately registered professionals.
- Support shaped around your team: from targeted advice to a fully outsourced ESOS assessment.
- Practical recommendations: a focus on achievable energy, cost and carbon savings rather than compliance paperwork alone.
- Management-system expertise: integrated support for ESOS, ISO 50001 and ISO 14001 where this adds value.
- Clear scope and pricing: agreed deliverables and a fixed-price proposal before work begins.
- Continuity beyond the deadline: support for action plans, annual progress updates and preparation for the next compliance phase.
Start preparing for ESOS
Whether you need help with the December 2026 progress update, an independent Lead Assessor, or a fully managed Phase 4 assessment, we can provide a clear and proportionate route forward.
Alternatively, contact our team for an initial, no-obligation discussion and fixed-price proposal.
ESOS Compliance FAQs
The Energy Savings Opportunity Scheme is a mandatory UK energy-assessment scheme for organisations that meet the qualification criteria. Qualifying participants must assess the energy used by their buildings, industrial processes, and transport every four years, identify energy-saving opportunities, and complete the required reporting and notifications.
ESOS generally applies to large UK undertakings and corporate groups containing at least one large UK undertaking. The Phase 3 thresholds were 250 or more employees, or both annual turnover above £44 million and an annual balance-sheet total above £38 million. The government decided not to align the Phase 4 thresholds with SECR, but organisations close to a threshold should confirm their status against the final Phase 4 guidance.
The Phase 4 compliance deadline is 5 December 2027. Organisations should begin earlier to confirm qualification, collect a suitable 12-month energy data set, schedule audits and allow time for Lead Assessor and board-level review.
The second annual progress update following Phase 3 is due by 5 December 2026. It records progress against the measures in the organisation’s ESOS action plan, must be approved by a board-level director or equivalent, and must be submitted through the government’s ESOS reporting service.
An ESOS assessment calculates total energy consumption, identifies significant energy consumption and audits relevant energy use across buildings, industrial processes and transport. It also identifies practical energy-saving opportunities and requires an evidence pack, an ESOS report, appropriate approval and notification to the scheme administrator.
Most organisations using the energy-audit route need a registered ESOS Lead Assessor to review the assessment and confirm that it meets the scheme requirements. A suitably qualified employee can act as Lead Assessor if registered with an approved professional body, or the organisation can appoint an external assessor.
Yes. For Phase 4, a certified ISO 50001 energy management system covering all energy consumption – or the significant energy consumption representing at least 95% of the total – can provide deemed compliance with specified ESOS assessment duties. Any energy consumption outside the certified system may still require separate treatment.
The relevant environmental regulator can take enforcement action and impose civil penalties for non-compliance. An organisation that has missed a deadline should not ignore it; it should review the official guidance, contact the regulator where appropriate and complete the outstanding work as soon as possible.
How can Equas help you?
Contact us for a no-obligation fixed-price quotation for ESOS compliance support.
