Services / ESOS Phase 4
ESOS Phase 4ESOS, done once and done right.
If your organisation is large on 31 December 2026, you must complete an ESOS assessment and notify the Environment Agency by 5 December 2027. We handle the lot, then use your data to make the savings real.
31 December 2026
Your size on this date decides whether you’re in Phase 4.
Compliance deadline
5 December 2027
Fixed quote within 48 hours of your enquiry.
ESOS applies to large UK organisations
You’re in scope if, on 31 December 2026, your organisation or any UK company in its group meets either test.
250 or more employees
Counted for the UK undertaking. If you pass this test, the financial test doesn’t matter.
Or turnover over £44m and balance sheet over £38m
Both financial thresholds must be met together.
Across your whole UK group
If one company in the group qualifies, the whole UK group is in scope and must comply together.
Source: GOV.UK, ESOS: find out if you qualify and how to comply. Close to the line? Use the form below and we’ll check it for you.
ESOS doesn’t end with the audit
Phase 4 runs to December 2027, and the action plan and progress updates carry on to 2031.
- 5 December 2026
Phase 3 second progress update
If you qualified for Phase 3, your second annual progress update on your action plan is due.
- 31 December 2026
Phase 4 qualification date
Your size on this date decides whether you’re in Phase 4. It applies across your whole UK group.
- 5 December 2027
Notification of compliance
Audit complete, signed off by a lead assessor and notified to the Environment Agency through MESOS.
- 5 December 2028
Phase 4 action plan
The energy-saving measures you commit to, with targets.
- 2029 · 2030 · 2031
Annual progress updates
Three yearly updates on your action plan, each due by 5 December. The third is new for Phase 4.
One team, from scoping to sign-off
You deal with Identic throughout. We own the data, the report and the relationship.
Scoping and qualification
We confirm which entities are in scope and set the 12-month reference period for your energy data.
Total energy consumption
Buildings, processes and transport, with at least 95% of your energy covered by the audit as Phase 4 requires.
Site audits
Audits of your significant energy use, using measured data from your incoming supply wherever we can.
Lead-assessor sign-off
Your assessment is reviewed and signed off by an accredited ESOS lead assessor working with us.
Notification through MESOS
We prepare your notification of compliance for the Environment Agency’s MESOS service and support board sign-off.
Action plan and progress updates
Your action plan and the three annual progress updates, drafted from live data rather than guesswork.
Progress updates from live data.
Most ESOS reports sit in a drawer. Yours plugs into the Identic EMS.
- Readers at your incoming supply measure each site from the start
- Every action-plan measure tracked against your own baseline
- Annual progress updates drafted from measured savings
- The same data sets you up for Phase 5
ESOS questions
We weren’t in Phase 3. Could we be in Phase 4?
Yes. Your position is assessed afresh on 31 December 2026. Growth, an acquisition or a change in group structure can bring you into scope even if you weren’t before.
How long does an ESOS assessment take?
For most organisations it takes a few months from data collection to sign-off, longer for large estates or fleets. Starting early gives you time to use a full year of measured data and to spread site visits sensibly before 5 December 2027.
Can we use a DEC or ISO 50001 instead?
From Phase 4, DECs and Green Deal assessments can no longer be used to comply. ISO 50001 still can, as long as the certificate was issued after 5 December 2023 and is still valid on 5 December 2027.
What happens if we don’t comply?
The Environment Agency can issue civil penalties and publish the names of organisations that haven’t complied. It has become more active on enforcement in recent phases.
Do we have to carry out the measures in the audit?
ESOS requires you to find and report energy-saving opportunities, and, since Phase 3, to submit an action plan and report progress against it. You choose which measures go in the plan. We help you pick the ones that pay back fastest, and our delivery partner GridUnlock can install them.
How much does it cost?
It depends on the number of sites, how much energy you use and how good your data is. Tell us about your organisation and we’ll send a fixed quote within 48 hours.
Two minutes now saves a scramble later.
Tell us about your organisation. We’ll confirm whether you’re in scope and send a fixed quote within 48 hours.
Are you in ESOS Phase 4?
Answer for your organisation as you expect it to be on 31 December 2026. Nothing is sent to us.
You’re likely in Phase 4.
Your audit must be signed off and notified by 5 December 2027. Get a fixed quote within 48 hours.
Get my fixed quoteYou’re likely outside Phase 4.
Your size on 31 December 2026 is what counts, so check again if you’re growing or acquiring. You can still cut costs with a free bill check or an Energy Fingerprint.
Let us check for you.
Group structures and overseas parents can change the answer. Send us the basics and we’ll confirm.
Ask us to checkNo obligation · fixed price · accredited lead-assessor sign-off. Prefer email? info@identic.energy
Your action plan is only worth what gets installed. Our delivery partner GridUnlock fits the measures (batteries, solar, EV charging, LED and controls) so your progress updates show real savings.
Batteries · Solar PV · EV charging · LED lighting · Controls