ESOS Phase 5 — 2027 to 2031
the dates, and what is not yet law
Qualification falls on 31 December 2030 and compliance on 5 December 2031. Neither date appears in any statutory instrument — and that is the most useful thing to know about Phase 5.
Two dates are reliable. Almost everything else about ESOS Phase 5 is someone’s guess
Phase 5 runs from 6 December 2027 to 5 December 2031. You qualify, or do not, on your position at 31 December 2030. That is the settled part.
What is not settled is everything the rest of the internet will tell you about Phase 5: that net zero audits become mandatory, that the qualification thresholds widen to match SECR, that enforcement tightens. Those are expectations. They are reasonable expectations, drawn from the direction the scheme has been travelling. But as at 14 August 2026 there is no Phase 5 legislation, no Phase 5 consultation, no Phase 5 draft guidance and no Phase 5 timetable — and a page that presents expectation as fact is not helping you plan.
So this page does something the others do not: it labels every claim.
Stated in an instrument
A statutory instrument says it, and we give you the regulation number so you can check.
Stated by the regulator
The Environment Agency or DESNZ says it. Authoritative, but not law, and it can change without Parliament.
Follows from law
It is the necessary consequence of a regulation, but no instrument states it. The Phase 5 dates are here.
There is a fourth label, and it does most of the work on this page: asserted — published by somebody with no primary source behind it. Where we use it, we name what was claimed and show what the law says instead.
Photo: Unsplash / Zac Wolff31 December 2030, and 5 December 2031
The qualification date is a single-day snapshot. The compliance date is the deadline by which the Environment Agency must have heard from you.
31 December 2030 — qualification. Your size on that one day decides whether Phase 5 applies to you at all. Not your average across the period, not your size when the period opens. One day.
5 December 2031 — compliance. By this date a qualifying organisation must have completed its ESOS assessment, had it reviewed by a lead assessor and notified the scheme administrator.
Both are derived, not legislatedRegulation 4 of SI 2014/1643 defines compliance periods as a rolling four-year cycle rather than naming individual phases. Apply it forward from Phase 4 and you get 31 December 2030 and 5 December 2031. The Environment Agency states both in its Phase 4 guidance of 30 July 2026 — but no statutory instrument does..
The word “phase” does not appear in the ESOS Regulations
Not once. Search the instrument and you will not find it.
The Energy Savings Opportunity Scheme Regulations 2014 know only two things: an initial compliance period and a subsequent compliance period. “Phase 1”, “Phase 4”, “Phase 5” are Environment Agency vocabulary and industry shorthand. They have no statutory existence at all.
Here is regulation 4, which is the entire machinery:
4.—(1) The “initial compliance period” means the period which begins on the coming into force of these Regulations and ends on 5th December 2015.
(2) A “subsequent compliance period” means a period which— (a) begins on the 6th December immediately following the end of the preceding compliance period, and (b) ends on the 5th December four years later.
(3) The “qualification date” means— … (b) in relation to a subsequent compliance period, the 31st December immediately preceding the compliance date for that compliance period.
Read it again and notice what it is doing. It is a self-perpetuating definition. Only two dates are written into it — 5 December 2015 and 31 December 2014 — plus a carve-out for Phase 3. Every period after that is generated by recursion: start on 6 December, run four years, qualify on the 31 December before the end.
Which means Phase 5 needs no legislation to exist. It already exists, in the same sentence that created Phase 2. And it also means that when a consultancy page tells you “the government has confirmed Phase 5 dates”, no such confirmation was ever needed or given. The dates were set in 2014 and nobody has had to touch them since.
This is not a technicality. It tells you what to watch for. Phase 5’s dates are about as stable as anything in UK compliance gets — they would take a new instrument to move. Phase 5’s content has no such protection: it can be changed by an amending SI at any point between now and 2031, exactly as SI 2026/701 changed Phase 4 mid-flight on 22 July 2026.
Five compliance periods, and where you are standing in them
Every date below is produced by applying regulation 4. Phase 3 is the one that breaks the pattern, and it is why so many guides disagree about “the ESOS deadline”.
Qualification dates are set by regulation 4(3)(b) — always the 31 December immediately preceding the compliance date. That single sentence is what makes one widely-published Phase 5 date impossible; see chapter 07.
Does Phase 5 make net zero audits mandatory?
Nobody knows. Including, on the published evidence, DESNZ.
Here is the honest sequence, each step sourced.
BEIS consults on strengthening ESOS, including adding a net zero element to audits. It closes that September.
Government publishes its response and commits to adding the net zero audit element in Phase 4.
The new government postpones mandatory net zero requirements from Phase 4 to Phase 5, citing delays to Phase 3 legislation and the scale of the change. SECR threshold alignment is deferred with it.
DESNZ says it expects to communicate further on Phase 5 plans, and on feedback opportunities for the PAS standards, “later in the year”.
Eighteen months on, no Phase 5 communication has appeared. No consultation, no call for evidence, no timetable.
Meanwhile, two things are widely assumed that are simply not true, and both are checkable in about a minute.
SI 2026/701 contains no net zero provision whatsoever. The July 2026 amendment is substantial — it omits four regulations and inserts a new chapter — and not one line of it concerns net zero.
The Environment Agency’s Phase 4 guidance never mentions PAS 51215. Not once, across roughly 33,000 words. The only occurrences of “net zero” in the document are in the name of the Department for Energy Security and Net Zero. The voluntary net zero option that everyone describes as part of Phase 4 lives entirely on the GOV.UK overview page and in the MESOS submission system — not in the law, and not in the operative guidance.
So when you read that Phase 5 “will require net zero audits”: what is actually on the record is a deferral, and a promise of further communication that is now a year and a half overdue. That is worth planning around. It is not worth budgeting against.
What carries into Phase 5 unless something changes it
Phase 5 inherits Phase 4’s machinery by default. These are the parts already in force that no announcement has touched.
250 staff, or £44m and £38m
A large undertaking employs at least 250 people, or has turnover over £44m and a balance sheet total over £38m. The financial limb is conjunctive — both, not either. The full test →
Still required
An assessment must be reviewed by a lead assessor on an approved register. No software removes that step. Exempt below 40,000 kWh total consumption, or where ISO 50001 covers all of it.
Never once amended
Up to £50,000 for failing to undertake an audit, and the same for a false or misleading statement. Set in 2014 and untouched by every amendment since.
Savings actually achieved
From 22 July 2026, an estimate in kWh of the savings you actually achieved, broken down by purpose, measure and category. This is the duty most likely to define Phase 5’s character.
Action plan review
You must identify measures from your action plan that were not implemented and are not expected to be — with reasons. ESOS has stopped being a tick-box audit.
DECs and Green Deal
Display Energy Certificates and Green Deal Assessments were removed as compliance routes on 22 July 2026. If your Phase 3 route was a DEC, you need a different one.
Five things published about ESOS that the legislation does not support
Each of these is currently live on at least one UK consultancy or advisory site. We checked every one against the primary source.
| Published claim | What the source actually says | Where to check |
|---|---|---|
| Phase 5 qualification date is 31 December 2027 | 31 December 2030. The claim is also self-contradictory: regulation 4(3)(b) makes the qualification date the 31 December immediately preceding the compliance date, and the same page gives that date as 5 December 2031. 31 December 2027 is not a qualification date for any ESOS period — it falls 25 days after Phase 5 opened. | reg 4(3)(b); EA guidance §3.1 |
| ESOS Phase 1 ran from 6 December 2011 | Phase 1 began 17 July 2014, when the Regulations came into force. 6 December 2011 is only the earliest date from which a pre-existing audit could be counted toward Phase 1 compliance — a different thing entirely. | reg 4(1); EA guidance §3.1 |
| You qualify on turnover over £44m or balance sheet over £38m | And. Schedule 1 paragraph 1(a) makes the financial limb conjunctive. Published as “or”, it pulls organisations into scope that are not in scope — the most consequential error on this list. | Sch 1 para 1(a) |
| ESOS fines reach £90,000 | No such figure exists. It is £50,000 plus 80 days at £500, i.e. the arithmetic ceiling of an aggregate penalty, republished as a headline maximum. The statutory maxima are £50,000 and £5,000, each with separately specified daily additions. | Part 8, regs 43–47 |
| The 2023 amendment is SI 2023/1364 | SI 2023/1182. SI 2023/1364 is not an ESOS instrument at all. SI 2026/701’s own footnote lists the relevant amendments as SI 2018/1342, SI 2020/711 and SI 2023/1182. | legislation.gov.uk |
One more, and it is ours. Until 14 August 2026 our own ESOS compliance guidance cited “regulation 29” as the source of the civil penalties. Regulation 29 is Notification of compliance; the penalties are Part 8, regulations 39 to 47. Corrected, and recorded here rather than quietly.
Will you qualify for Phase 5 on 31 December 2030?
Nobody can answer that for 2030. But the test itself is unchanged since 2018, so you can find out whether you would qualify today — which is the only useful proxy.
The test applies Schedule 1 paragraph 1(a) of SI 2014/1643 as amended: at least 250 employees, or turnover above £44m and balance sheet total above £38m. It is a guide, not a determination — group structures, overseas parents and the insolvency exclusion all change the answer.
What is worth doing before Phase 5, and what is not
Four years is long enough to over-prepare for requirements that may never arrive. Here is the split.
The new duty to report savings actually achieved, in kWh, broken down by measure, is the hardest of the 2026 changes to retrofit. If your data cannot support it for Phase 4, it will not support whatever Phase 5 asks either.
Every ESOS change since 2014 has asked for more granularity from the same underlying activity data. That is the safe bet regardless of what Phase 5 turns out to require.
Phase 5 content will arrive as a consultation before it arrives as an instrument. That consultation is the moment to engage, and it is now eighteen months overdue.
Part 1 is voluntary in Phase 4 and is not mentioned in the Environment Agency’s guidance at all. A vendor selling “Phase 5 net zero readiness” today is selling against a specification nobody has written.
SECR alignment was deferred, not decided. SI 2026/701 left Schedule 1 untouched. Plan on the current test.
ESOS Phase 5 FAQs
5 December 2031. The qualification date — the single day on which your size decides whether Phase 5 applies to you — is 31 December 2030, and the compliance period runs from 6 December 2027 to 5 December 2031. Both dates follow from regulation 4 of the ESOS Regulations 2014 and are stated in the Environment Agency’s Phase 4 guidance of 30 July 2026, though no statutory instrument names them.
The dates are, in effect — but not in the way most sources imply. The word “phase” does not appear in the ESOS Regulations 2014 at all. Regulation 4 defines a rolling four-year cycle of compliance periods, which generates Phase 5’s dates automatically without any further legislation. What is not settled is Phase 5’s content: as at 14 August 2026 there is no Phase 5 instrument, consultation, draft guidance or timetable.
It is intended, but not committed. Government consulted on adding a net zero element in 2021, said in July 2022 it would come in Phase 4, then in February 2025 postponed it to Phase 5. DESNZ said at that point it would communicate further on Phase 5 plans “later in the year”; eighteen months later nothing has been published. SI 2026/701 contains no net zero provision, and the Environment Agency’s Phase 4 guidance does not mention PAS 51215 at any point.
Alignment of ESOS thresholds with SECR was consulted on and then deferred, alongside the net zero element. SI 2026/701 left Schedule 1 untouched on 22 July 2026, so the test remains at least 250 employees, or turnover above £44 million and a balance sheet total above £38 million. Note that the financial limb is conjunctive — both, not either — which is published incorrectly on many UK advisory sites.
Phase 4 is running now: qualify on 31 December 2026, comply by 5 December 2027, under rules amended by SI 2026/701 on 22 July 2026 — which removed Display Energy Certificates and Green Deal Assessments as compliance routes and added reporting of savings actually achieved, an action plan review and a third progress update. Phase 5 opens on 6 December 2027 and inherits all of that by default, because nothing has been published to change it.
Prepare for the data, not the requirements. Every ESOS change since 2014 has asked for more granularity from the same underlying activity data, so improving that is the safe investment regardless of what Phase 5 specifies. What is not worth doing is buying against a Phase 5 net zero mandate: the specification does not exist yet, and the consultation that would create it has not been published.
Primary sources
Every legal statement on this page carries an inline citation. These are the documents behind them, each opened and read on 14 August 2026.
A note on reading the legislation yourself: as at 14 August 2026 the SI 2026/701 amendments are still marked “not yet applied” to the consolidated text on legislation.gov.uk. The “Latest Available (Revised)” version of SI 2014/1643 therefore shows pre-July-2026 law in most places. Read the amending instrument alongside it, not instead of it.
The rest of the ESOS cluster
ESOS Phase 4 compliance
The period you are actually in. Qualify 31 Dec 2026, comply 5 Dec 2027.
The cycleAll five ESOS phases
Every qualification and compliance date since 2014, and why Phase 3 breaks the pattern.
The lawThe ESOS regulations
SI 2014/1643 and every amendment, including what changed on 22 July 2026.
ScopeDo you qualify?
250 employees, or £44m and £38m — and why “or” is wrong.