ESOS Phase 4: notification deadline 5 December 2027

ESOS compliance checklist

An ESOS compliance checklist for Phase 4 of the Energy Savings Opportunity Scheme, from the ESOS Phase 4 qualification date to notification.

Work through ESOS alongside the UK SRS disclosures your organisation may be preparing.

Start the checklist →All compliance deadlines

The scheme

What is ESOS?

The Energy Savings Opportunity Scheme (ESOS) is a mandatory energy assessment scheme for UK organisations that meet the qualification criteria, established by The Energy Savings Opportunity Scheme Regulations 2014.

ESOS applies to large undertakings.

It requires them to assess the energy used for each of four organisational purposes: buildings, industrial processes, transport, and any other purpose not falling within those three.

The checklist

Seven steps from qualification to notification

Tick each one off in order; the dated steps are the ones the Regulations hang a deadline on.

STEP 1Determine qualification31 Dec 2026
Assess whether your organisation qualifies as at 31 December 2026, testing the corporate group position as well as the individual entity.
STEP 2Deal with any live Phase 3 obligation5 Dec 2026
If you notified in Phase 3, Progress Update 2 is due by 5 December 2026.
There is no penalty for missing it, but the failure is published on the public register.
STEP 3Measure total energy consumption
Calculate your organisation’s total energy use across all four organisational purposes:
- Buildings (electricity, gas, other fuels)
- Industrial processes
- Transport (vehicles and fuel your organisation is supplied with)
- Any other purpose not falling within those three
STEP 4Identify areas for energy audits
Select areas that represent at least 95% of total energy consumption for detailed auditing.
STEP 5Conduct energy audits
Engage a Lead Assessor on a currently approved register to sign off the assessment and identify energy saving opportunities.
STEP 6Consider energy efficiency recommendations
Review audit findings and consider implementation of energy efficiency measures, following the step-by-step delivery detail for each stage.
STEP 7Submit compliance notification5 Dec 2027
Submit compliance notification to the Environment Agency by 5 December 2027, then the Action Plan by 5 December 2028.

Step 1 in detail

ESOS qualification criteria

Your organisation is a “large undertaking” for ESOS if it meets either of the tests set out in Schedule 1 to the ESOS Regulations 2014 and restated in the Environment Agency’s Phase 4 guidance.

Note the structure: there is an OR between the two limbs but an AND inside the financial limb, so exceeding the turnover figure alone does not qualify you.

Group aggregation also applies — an undertaking in a group containing at least one large undertaking on the qualification date is in scope even if it is individually below the test.

The test is worked through case by case on our ESOS thresholds page, and the wider question of whether you must comply is answered in is ESOS mandatory?

SECR works the other way round

Under paragraph 20B of Schedule 7 to the 2008 Accounts Regulations, an unquoted company is exempt from SECR where it meets two or more of turnover not more than £36m, balance sheet total not more than £18m, or not more than 250 employees.

SI 2026/701, the Phase 4 amending instrument in force from 22 July 2026, left the ESOS thresholds untouched.

So the two regimes continue to use different tests, and an organisation can be in scope of one and not the other — see ESOS vs SECR.

A large undertaking meets either test

Employee test

At least 250 employees

Financial test — both limbs

Turnover in excess of £44 million and balance sheet total in excess of £38 million

Source: SI 2014/1643, Schedule 1

The dates

ESOS Phase 4 qualification date and timeline

Qualification is determined at a single point in time called the ‘qualification date’.

For ESOS Phase 4 that date is 31 December 2026: regulation 4(3)(b) of the ESOS Regulations 2014 fixes it as the 31 December immediately preceding the compliance date, and the ESOS Phase 4 guidance states it directly.

Your position on that date fixes your scope for the whole phase, whatever happens after it.

These dates are now tabulated explicitly in the Environment Agency’s Phase 4 guidance, published 30 July 2026.

The third progress update is new in Phase 4, added by regulation 28 of SI 2026/701.

The action plan and every progress update need director (or equivalent) sign-off and are submitted through MESOS.

Every date in the phase, with what each one requires, is on our ESOS Phase 4 deadline page.

For the step-by-step route to the December 2027 deadline, see the full ESOS Phase 4 compliance guide on uksrs.org.uk.

6 Dec 2023 – 5 Dec 2027
Compliance period
Per GOV.UK ESOS Phase 4 guidance.
5 Dec 2026
Phase 3 Progress Update 2
A live obligation for organisations that notified in Phase 3.
31 Dec 2026
Qualification date
5 Dec 2027
Compliance (notification) deadline
5 Dec 2028
Action plan
Covering 6 December 2027 – 5 December 2031.
5 Dec 2029, 2030, 2031
Progress updates

Steps 4 to 7 in detail

ESOS compliance requirements

Three things have to be true before the notification goes in: the audit coverage, the route, and the sign-off.

1 · Energy audits

What the audit must cover

At least 95% of total energy consumption — the de minimis was cut from 10% to 5% by SI 2023/1182.
Signed off by a Lead Assessor on a currently approved register.
All four organisational purposes: buildings, industrial processes, transport, and any other purpose not falling within those three.
Cost-effective energy efficiency opportunities identified.

2 · Alternative routes

ISO 50001 and hybrid

ISO 50001: where certification covers total or significant energy consumption, the participant is deemed to have complied with the duties to appoint a lead assessor, carry out the energy audit and produce the ESOS report — a notification of compliance is still required.
Hybrid: partial ISO 50001 coverage exempts only the certified consumption; the remainder needs an ESOS energy audit and a lead assessor.

3 · Sign-off

Responsible officers

One or more “responsible officers” must be nominated per regulation 30(2) — a director within s.250 Companies Act 2006, or a person exercising management control.
“Board level” is guidance shorthand and does not appear in the Regulations.
One responsible officer where the lead assessor is independent of the participant (regulation 30(3)); two in any other case.
Independence is defined exhaustively in regulation 30(4), so a consultant who was an employee, director or shareholder in the previous 12 months does not count as independent.
Two responsible officers where no lead assessor was appointed — under the 40,000 kWh threshold, or zero energy consumption.

DECs and Green Deal Assessments are removed

Display Energy Certificates and Green Deal Assessments are removed as ESOS compliance routes: regulation 26 of SI 2026/701 omits regulation 34 of the 2014 Regulations.

Data collected for a DEC or GDA can still feed the ESOS report, for example an energy intensity ratio, but it cannot stand in for the audit.

Organisations that relied on either in Phase 3 need a full energy audit or expanded ISO 50001 scope.

Check your lead assessor’s register

The Institution of Chemical Engineers was removed from the list of approved registers for ESOS lead assessors on 16 February 2026.

Anyone whose lead assessor was IChemE-registered should confirm their standing on a currently approved register.

Enforcement

Penalties: where they actually bite

ESOS enforcement is asymmetric.

Penalties attach to the compliance-date obligations — up to £50,000 plus up to £40,000 in daily penalties (£500 per working day, capped at 80 working days) for failure to undertake an assessment.

But there is no direct penalty for non-submission of an action plan or a progress update: regulations 34A and 34B are named nowhere in Part 8’s penalty chapter, a genuine statutory gap rather than forbearance.

The primary consequence is publication of the failure on the public register.

There is a residual route: an enforcement notice served under regulation 38 requiring an action plan carries the standard penalty (regulation 46(1)) if not complied with — £5,000 plus £500 per working day, capped at 80 working days.

£50,000

Maximum penalty for failure to undertake an assessment

£40,000

Plus daily penalties: £500 per working day, capped at 80 working days

Source: SI 2014/1643, Part 8
Obligation	Direct penalty?
Compliance-date obligations	Yes
Action plan (reg 34A)	No — publication on the public register
Progress update (reg 34B)	No — publication on the public register
Enforcement notice under reg 38	Yes — £5,000 plus £500 per working day, capped at 80 working days (reg 46(1))

Joining up

Integration with UK SRS

ESOS compliance can support your UK SRS preparations under UK SRS S2 climate disclosure requirements, particularly for the four areas below.

Energy efficiency data

ESOS audits provide baseline energy consumption data.

Scope 1 & 2 emissions

Energy audits help quantify direct and indirect emissions.

Improvement opportunities

Energy efficiency measures support climate transition planning.

Governance structures

Board-level oversight aligns with climate governance requirements.

Next step

Getting started

Begin your ESOS Phase 4 compliance preparation by assessing your current energy consumption and identifying lead assessors on an approved register for your sector.

How to compare candidates is set out in our ESOS consultant selection criteria, and what a full engagement covers in ESOS reporting services.

For the regulatory detail behind each item on this checklist, see the ESOS compliance guidance on uksrs.org.uk.

UK SRS integration guide All compliance deadlines

Sources

Primary sources

Every figure, date and status on this page traces to the instrument’s owner. Secondary commentary is never the source for a number.

Checked against 13 sources fromEnvironment AgencyGOV.UKlegislation.gov.ukDepartment for Business and Trade

Environment Agency
Comply with the Energy Savings Opportunity Scheme (ESOS) phase 4
Published 30 July 2026: the qualification test, the Phase 4 date table and the ISO 50001 deemed-compliance route.
GOV.UK
Energy Savings Opportunity Scheme (ESOS) — guidance
The scheme overview, including the 16 February 2026 removal of IChemE from the approved lead assessor registers.
legislation.gov.uk
The Energy Savings Opportunity Scheme Regulations 2014 (SI 2014/1643)
The instrument that establishes ESOS.
legislation.gov.uk
ESOS Regulations 2014, Schedule 1
The large-undertaking test: at least 250 employees, or turnover in excess of £44m and balance sheet total in excess of £38m.
legislation.gov.uk
ESOS Regulations 2014, regulation 4
The compliance period formula; regulation 4(3)(b) fixes the qualification date as the 31 December before the compliance date.
legislation.gov.uk
ESOS Regulations 2014, regulation 30
Responsible officers: who may sign off (30(2)), how many (30(3)) and the independence test (30(4)).
legislation.gov.uk
ESOS Regulations 2014, Part 8 — enforcement and penalties
The penalty chapter, which names no penalty for regulations 34A and 34B.
legislation.gov.uk
ESOS (Amendment) Regulations 2023 (SI 2023/1182)
Cut the de minimis from 10% to 5%, giving the 95% audit coverage rule.
legislation.gov.uk
ESOS (Amendment) Regulations 2026 (SI 2026/701)
The Phase 4 amending instrument, in force 22 July 2026; left the qualification thresholds untouched.
legislation.gov.uk
SI 2026/701, regulation 26
Omits regulation 34 of the 2014 Regulations, removing DECs and Green Deal Assessments as compliance routes.
legislation.gov.uk
SI 2026/701, regulation 28
Adds the third progress update.
legislation.gov.uk
SI 2008/410, Schedule 7, paragraph 20B
The SECR exemption test, for comparison with the ESOS qualification test.
Department for Business and Trade
UK Sustainability Reporting Standards (UK SRS S1 and UK SRS S2)
The standards published on 25 February 2026, including the S2 climate disclosures.