ESOS compliance services — matched with an approved Lead Assessor

What our ESOS compliance services cover

ESOS compliance services take a large organisation through the Energy Savings Opportunity Scheme from start to sign-off without tying up your own team. We use an introduction model: rather than employ named consultants or file on your behalf, we match you with a single approved ESOS Lead Assessor whose firm handles the audit, energy intensity ratio, mandatory action plan and notification end to end. ESOS is a mandatory energy assessment scheme under the ESOS Regulations 2014, and Phase 4 is the live obligation now — so the work needs a registered assessor, not a generalist.

A complete service includes:

• Eligibility confirmation — checking whether you qualify for ESOS and, where relevant, SECR too.
• Total energy consumption measurement across buildings, processes and transport over a 12-month reference period.
• Energy audits covering at least 90% of your significant energy use.
• An energy intensity ratio, now required in Phase 4.
• A mandatory action plan committing to cost-effective energy efficiency measures.
• Assessor sign-off and notification to the regulator.

Who needs ESOS compliance services

ESOS qualification is separate from SECR, and the thresholds are different. You are a large undertaking caught by ESOS Phase 4 if, on the qualification date, you are a UK organisation that meets either test below.

• 250 or more employees, or
• an annual turnover in excess of £44 million and a balance sheet total in excess of £38 million.

Corporate groups qualify together where the highest UK parent is caught, and overseas groups with a qualifying UK presence are in scope too. These are the ESOS thresholds only. SECR uses a different test — turnover of at least £36 million, balance sheet total of at least £18 million, or at least 250 employees, where two of the three are met. Because the April 2025 Companies Act uplift raised the general "large" turnover and balance-sheet limits but left the SECR thresholds untouched, a company now classed as "medium" can still be in scope for SECR. Our eligibility checker settles it in a couple of minutes.

Why use a specialist rather than DIY

In-house energy data is rarely audit-ready, and ESOS notifications must be signed off by an assessor on the approved register — that sign-off cannot be sub-contracted to a generalist consultant. A specialist provides three things a DIY route struggles to match: a registered assessor who carries the sign-off, an evidence pack that withstands the tougher Phase 4 regulator review, and an action plan that turns the audit into a costed shortlist of energy efficiency measures rather than a box-ticking exercise. That also keeps you clear of the £50,000-plus penalties that attach to a late or misleading notification.

How matching works

This site is free to use. You tell us about your organisation, and we connect you with one vetted, IEMA-qualified, approved ESOS Lead Assessor — we do not employ named consultants or file the assessment ourselves.

1. Tell us about your organisation — headcount, turnover, sites and energy use.
2. We match you with a single registered assessor suited to your sector and footprint.
3. You get a fixed-fee quote within one working day, with no obligation.
4. The assessor delivers the audit, action plan and notification to the 5 December 2027 deadline.

What an ESOS assessment involves

Your ESOS report is built from the assessment, which runs through a clear sequence:

1. Measure total energy consumption across buildings, industrial processes and transport over a 12-month reference period.
2. Identify your areas of significant energy use — the assets and activities that make up at least 90% of consumption.
3. Carry out energy audits of that significant energy use, or cover it through an approved alternative route.
4. Identify cost-effective energy efficiency opportunities, each with an estimated cost, saving and payback.
5. Build the mandatory action plan committing to the measures you intend to take.
6. Assessor sign-off, then notify the regulator.

Typical routes to cover your energy use include a full ESOS energy audit, a Display Energy Certificate, a certified ISO 50001 energy management system, or another recognised alternative route. Organisations with ISO 50001 certification covering their full energy use can often lean on it as their main route. Your assessor confirms the right mix, and sign-off is never sub-contracted.

What's new in ESOS Phase 4

Three changes matter most this phase:

1. The action plan is now mandatory. You must commit to specific energy-saving opportunities with timelines, not just identify them, and follow up with a progress update in later years.
2. An energy intensity ratio is now required, so your energy consumption is reported against a business metric — energy per square metre, per unit of output or per employee.
3. Tougher regulator review of significant energy use definitions and overall audit quality, which raises the bar on the evidence behind every figure.

Phase 3 closed on 5 December 2023, so Phase 4 is the obligation to plan for now. The key dates are a qualification date of 31 December 2026 and a compliance deadline of 5 December 2027, by which the notification and mandatory action plan must reach the Environment Agency. The reference period your energy audits cover is the 12 months up to the qualification date, so the data you collect in 2026 is the data you report — leaving it late risks a rushed assessment and a shortage of approved assessors.

Pricing and combined ESOS and SECR compliance

Most large UK organisations qualify for both ESOS and SECR, and the underlying energy and carbon data overlaps substantially. Where you need both, the assessor can scope them as a single combined engagement, which is usually more efficient than commissioning each separately. Fees depend on your number of sites, energy use and chosen route, which is why every match comes with a tailored fixed-fee quote rather than a headline rate — see our pricing for how that works. For wider context, read the SECR vs ESOS comparison and our SECR reporting services. To move beyond compliance, the same data can feed a net zero strategy or carbon footprint calculation.

Penalties for missing ESOS

ESOS is enforced. The Environment Agency can issue a fixed penalty of up to £50,000 for failing to notify, plus £500 for each working day the breach continues (up to 80 days), and further penalties for an inadequate evidence pack or a false or misleading notification. Enforcement action can also be published. Many public-sector and large corporate buyers screen suppliers for it, so a lapse carries procurement and reputational risk as well as a direct cost. The Environment Agency administers the scheme for most of the UK, with the Scottish Environment Protection Agency and the equivalent bodies in Wales and Northern Ireland acting as regulators in the devolved nations.

Get matched with an ESOS specialist

Ready to start your Phase 4 assessment? Tell us about your organisation and we will match you with one approved ESOS Lead Assessor, free of charge. Start with our eligibility checker or deadline calculator, then get matched.