Preparing for ESOS Phase 4: A Complete Checklist for UK Businesses

Preparing for ESOS Phase 4: A Complete Checklist for UK Businesses

The Energy Savings Opportunity Scheme (ESOS) is now in its fourth phase, running from 6 December 2023 through to 5 December 2027. As UK businesses face growing pressure to improve efficiency and reduce carbon emissions, ESOS Phase 4 presents both a regulatory obligation and a valuable strategic opportunity.

With mandatory Action Plans now required and increased scrutiny around audit quality, early preparation is not just encouraged; it’s essential. This guide provides a comprehensive checklist to help you comply confidently, avoid penalties, and extract real value from the process.

Whether you’re managing a large property portfolio, overseeing manufacturing operations, or responsible for corporate sustainability reporting, Inteb can help you meet your obligations and realise measurable results.

Explore our ESOS Compliance Services to get started.

What Is ESOS and Why Does It Matter?

The Energy Savings Opportunity Scheme (ESOS) is a mandatory UK government programme that requires large organisations to assess their energy use and identify opportunities for cost-effective savings every four years. It forms part of the UK’s broader strategy to reduce greenhouse gas emissions and improve industrial and commercial energy performance.

The scheme is administered by the Environment Agency in England and is legally binding under the Energy Savings Opportunity Scheme Regulations 2014 (as amended). Failure to comply can result in fines of up to £50,000, along with additional daily penalties.

But beyond regulatory compliance, ESOS provides valuable insights. A thorough audit and action plan can uncover hidden inefficiencies, cut utility costs, and support wider sustainability goals; including SECR, ISO 50001 and Net Zero strategies.

Who Needs to Comply with ESOS Phase 4?

If your organisation operates in the UK and met any of the following criteria on the qualification date of 31 December 2026, you are legally required to comply with ESOS Phase 4:

• Employed 250 or more people
• Had an annual turnover over £44 million and a balance sheet total over £38 million
• Was part of a corporate group that meets either threshold

If you’re unsure whether your organisation qualifies, Inteb can carry out a free eligibility check to confirm your obligations and help you plan the next steps.

Key Dates for ESOS Phase 4

• Qualification date: 31 December 2026
• Compliance period: 6 December 2023 to 5 December 2027
• Submission deadline: 5 December 2027

While the deadline may appear distant, the audit, analysis, and reporting processes can take months. The most successful organisations are those that begin early and treat ESOS as a rolling programme rather than a last-minute task.

Preparing for ESOS Phase 4: A complete checklist for UK businesses ensures nothing is missed in energy compliance reporting.

ESOS Phase 4 Compliance Checklist

Here’s your step-by-step breakdown of what’s required for full ESOS Phase 4 compliance:

1. Confirm Eligibility

Verify whether your business meets the size or financial thresholds outlined above. For complex organisational structures, a group-level assessment may be required.

2. Appoint an ESOS Lead Assessor

Only a qualified and accredited ESOS Lead Assessor can oversee and sign off your submission. They will work with you to guide the audit process and verify your findings.

3. Measure Total Energy Consumption

Accurate data is at the heart of ESOS. You must account for 100% of your total energy usage, including:

• Buildings
• Transportation
• Industrial operations
• Any outsourced energy consumption

This data must be gathered over a continuous 12-month period that includes 31 December 2026.

4. Identify Significant Energy Use

At least 90% of your total energy consumption must be audited. These are known as “significant energy use areas” and will become the focus of your site assessments.

5. Conduct Energy Audits

Energy audits must include:

• Site inspections
• Equipment analysis
• Operating pattern reviews
• Data benchmarking
• Actionable energy-saving recommendations

Audits must meet the minimum quality standard set out in BS EN 16247 or be completed under ISO 50002.

6. Document Your Methodology

You must clearly explain how your consumption data was collected, how significant energy areas were chosen, and how your recommendations were derived.

7. Compile Your ESOS Report

This document outlines your audit findings, methodology and savings opportunities. It must be reviewed and approved by both the Lead Assessor and a Board-level director.

8. Develop a Mandatory Action Plan

New in Phase 4, Action Plans must set out how your organisation intends to act on audit recommendations. These must be submitted alongside your main report and demonstrate realistic, measurable follow-up.

9. Submit to the Environment Agency

Both the ESOS report and Action Plan must be submitted online via the ESOS compliance portal by the 5 December 2027 deadline.

10. Begin Implementation and Monitoring

While implementation is not currently mandatory, Phase 4 introduces a stronger expectation of follow-through. Progress against Action Plans may be publicly disclosed in the future.

What’s Different in Phase 4?

The fourth phase of ESOS introduces the most significant changes to date. These include:

• Mandatory Action Plans outlining intended follow-up
• Stronger alignment with Net Zero and ESG frameworks
• Greater audit standardisation and tighter quality controls
• More robust Lead Assessor involvement
• Increased enforcement activity and data scrutiny

Inteb ensures that your Phase 4 submission meets the latest standards and aligns with future regulatory trends.

Behind the scenes of ESOS Phase 3 reporting: how a TV and film production company achieved compliance with expert support.

Case Study: ESOS Phase 3 compliance

A global independent television and film production and distribution company engaged Inteb to support and develop the compliance related documentation for ESOS Phase 3. We were able to help them to achieve 100% Significant Energy Consumption (SEC) coverage. We conducted energy assessments across 15 sites and identified multiple energy efficiency opportunities in lighting, sub-metering, HVAC and smart controls. The assessment also aligned with the client’s ISO 50001 Energy Management System certification.

By implementing our recommendations, the client is poised to realise energy savings of up to 151,433 kWh in 2025 itself, with potential annual savings accumulating in future.

ESOS in the Bigger Picture

ESOS compliance is just one piece of the energy management puzzle. Inteb works with clients to integrate ESOS into broader programmes including:

• SECR (Streamlined Energy and Carbon Reporting)
• MEES (Minimum Energy Efficiency Standards)
• ISO 50001 (Energy Management Systems)
• Corporate Net Zero planning
• Tenant billing and operational ESG frameworks

We help you maximise your return on compliance through integrated, strategic thinking.

Don’t Wait Until 2027; Start Now

With more complexity and higher expectations in Phase 4, the earlier you start, the better positioned you’ll be to succeed. Inteb offers:

• Lead Assessor appointment
• Full audit planning and execution
• Tailored Action Plan development
• Submission support
• Post-compliance implementation and tracking

Have questions about ESOS Phase Four? Visit our homepage to speak with our energy experts. #justaskceejay

Book Your ESOS Phase 4 Consultation

ESOS Phase 4 compliance doesn’t need to be a burden. With Inteb, it becomes an opportunity to improve performance, reduce costs, and demonstrate leadership in sustainability.

Contact us today to book your free ESOS Phase 4 consultation and start your journey with confidence.