ESOS energy audit
Lead assessor, regulation 27 audit of at least 95% of consumption, ESOS report.
Audit software produces the regulation 27 outputs.Software · ESOS energy audits, cited
Energy audit software: what an ESOS audit must produce
Energy audit software turns meter, bill and site data into an energy audit: where energy goes, what could be saved, and what each saving costs and returns.
In the UK the template is the ESOS energy audit in regulation 27; this page sets out the outputs it asks for, the parts no software can do, and the tests to run before you buy.
What the software does
What does energy audit software actually do?
An energy audit answers one question: where does this organisation use energy, and what could it reasonably and cost-effectively do to use less?
Regulation 27 of the ESOS Regulations 2014 turns that into a list of outputs, and software earns its place by producing them from your data rather than from a fresh spreadsheet each phase.
The audit sits inside a larger ESOS assessment: a total energy figure for the group, the 95% coverage test, intensity ratios, the ESOS report and the notification of compliance, set out on ESOS energy audit.
The data underneath usually comes from the same meters and bills as SECR, which is where energy monitoring software fits.
- 1
Total
All UK energy of the group for a 12-month reference period, in kWh or pounds.
- 2
Cover
Pick the assets and activities that make up at least 95% of it.
- 3
Profile
Break consumption down by use and look at how it varies.
- 4
Find
Identify and cost each opportunity: pounds, kWh, payback.
- 5
Programme
Recommend an order and timescale; carry it into an action plan.
Regulation 27, line by line
What must an ESOS energy audit contain?
Each row is a duty in regulation 27, as amended in 2023 and 2026, and what to look for in a tool.
| Output | Provision | What to check in a tool |
|---|---|---|
| Analysis of energy consumption and efficiency | reg 27(1)(a) | Built from your meter and bill data, by site and by use |
| Energy consumption profiles | reg 27(2)–(3) | A breakdown by activity and asset, with variation where appropriate; or a recorded alternative method |
| Ways to improve efficiency, and recommended measures | reg 27(1)(b)–(c) | Only measures reasonably practicable and cost effective for you |
| Organisational purpose and energy saving category for each | reg 27(1)(d)(i)–(ii) | Buildings, industrial processes, transport, or other |
| Costs and benefits in pounds; non-financial costs and benefits | reg 27(1)(d)(iv)–(v) | Whole-life cost where practicable, under reg 27(5) |
| Annual saving in spend and in kWh | reg 27(1)(d)(vi) | kWh is required since 22 July 2026 |
| Payback period | reg 27(1)(d)(vii), (7) | Cost divided by the annual saving in energy cost, in years |
| Recommended programme | reg 27(1)(e) | Timescale, programme cost and benefit, programme payback |
Regulation 27 also asks for any considerations relevant to implementation, including obligations under the minimum energy efficiency rules for rented buildings and any public grant schemes that might help.
The duties apply “so far as reasonably practicable”, so a tool that records why a site or a measure was not analysed is doing part of the job too.
The 95% test
How much of your energy does the audit have to cover?
The audit must cover the assets and activities that together account for at least 95% of total energy consumption, measured in energy units or in energy spend, under regulation 25(2).
The figure was 90% until SI 2023/1182 changed it from 29 November 2023, so guides that still say 90% are describing an earlier phase.
Total energy consumption is all UK energy of the participant, normally the whole group, in one common unit, and carbon dioxide is not an energy unit, according to the Environment Agency’s Phase 4 guidance.
The calculator beside this lists your energy uses and shows which ones you need to audit to reach 95%.
The 95% floor · reg 25(2)
Total 0 kWh · covered 0% · left as de minimis 0%
Enter figures to test coverage.
SI 2014/1643 regs 21(3), 25(1)–(2), 30(3A); Environment Agency Phase 4 guidance §§5, 8.3.
Use one 12-month reference period for every row.
Nothing entered leaves the page.
People, not software
What can energy audit software not do for you?
ESOS needs a lead assessor on an approved register, which regulation 12 ties to the PAS 51215 competence standard, unless total energy consumption is less than 40,000 kWh or an ISO 50001 certificate covers total or significant consumption.
Since 22 July 2026 the lead assessor also has a personal duty to notify their approval body within seven days, under the new regulation 21(2A) inserted by SI 2026/701.
The assessment is signed off at board level and submitted through MESOS, the Environment Agency’s service.
So the honest description of energy audit software is a tool that does the arithmetic and keeps the record, so that the assessor and the board can spend their time on the judgements.
Read the detailed guidance and references
The Environment Agency puts the duty to verify an assessor’s approval on the undertaking at the time of the assessment, and seven professional bodies maintain approved registers, among them ISEP.
A participant whose total energy consumption is zero needs no assessment and no lead assessor under the new regulation 33A, but still notifies compliance.
How the assessor role works is on ESOS lead assessor.
Four things stay with peopleExplore
Four things stay with people
The lead assessor
An individual on an approved register, unless consumption is under 40,000 kWh or ISO 50001 covers it.
Four things stay with people
The board sign-off
The assessment and its notification are confirmed by the responsible officer at board level.
Four things stay with people
What is cost effective
A judgement on your costs and savings, made measure by measure.
Four things stay with people
The register check
The undertaking must verify the assessor’s approval when appointing them.
Phase 4 dates
When does the Phase 4 audit have to be done?
- 6 December 202301
- 22 July 202602
SI 2026/701 in force
Savings in kWh, the action plan review, savings achieved; DECs and GDAs removed. - 31 December 202603
- 5 December 202704
- 5 December 202805
Action plan due
Measures, dates and estimated savings in kWh, covering to 5 December 2031.
Audit data must start no earlier than 12 months before the compliance period begins and no earlier than 24 months before the audit itself, according to the Environment Agency’s guidance, so a tool with two clean years of history covers the window.
The reference period for total energy consumption is 12 consecutive months beginning no more than 12 months before the qualification date and ending by the compliance date, under regulation 22(5).
The full calendar is on ESOS deadlines.
Two routes
Audit or ISO 50001: which route does the software serve?
Phase 4 has two routes and only two: the ESOS energy audit, and ISO 50001 certification covering total or significant energy consumption.
Display Energy Certificates and Green Deal Assessments stopped being routes on 22 July 2026, though their data can still feed an ESOS report.
An organisation on the ISO 50001 route needs energy management software more than audit software, because ISO 50001 asks for continual improvement in energy performance, tracked with indicators and baselines.
Where certification covers only part of consumption, the rest still needs an audit and a lead assessor.
Phase 4
participant
participant
ISO 50001 certification
Where it covers total or significant consumption, the audit, assessor and report duties are treated as met.
Energy management software runs the system; notification is still due.Savings achieved
How do you show the savings were real?
Phase 4 added a duty to report the energy savings actually achieved from measures implemented in the compliance period, in kWh, by measure and by organisational purpose, through the new regulation 27D.
It also added an action plan review: which measures from the last action plan were not implemented, and why.
No UK rule prescribes how to measure a saving, but the International Performance Measurement and Verification Protocol sets out four options and is the common reference, from the Efficiency Valuation Organization.
Audit software that keeps the baseline from one phase to the next is what makes the savings figure reproducible.
Four ways to measure a savingExplore
What is at stake
What happens if the audit is not done?
Audit penalty
£50,000Or a lesser amount — reg 45Daily penalty
£500Per working day, up to 80 working daysCoverage
95%Of total energy consumption — reg 25(2)Lead assessor threshold
40,000 kWhBelow it, no assessor needed — reg 21(3)Part 8 of the ESOS Regulations sets the penalties, and failing to carry out an energy audit carries the largest.
Part 8 names no penalty for failing to submit an action plan or a progress update, which is a gap in the statute rather than the regulator choosing not to act.
The full schedule is on ESOS penalties.
| Failure | Penalty | Provision |
|---|---|---|
| Not carrying out an energy audit | £50,000, or a lesser amount the compliance body decides, plus up to £500 per working day for up to 80 working days | reg 45 |
| False or misleading statement | £50,000, or a lesser amount | reg 47 |
| Failure to notify compliance | Up to £5,000, plus up to £500 per working day for up to 80 working days | reg 43 |
| No action plan or progress update | No penalty named in Part 8 | regs 43–47 |
The tests before you sign
Which questions separate an audit tool from a dashboard?
Each question beside this names the provision it comes from and what a passing answer looks like.
Run them on your own data: a demonstration estate never has an estimated bill, a missing sub-meter or a site sold half-way through the year.
This site has tested no products
Nothing on this page is a rating, ranking or recommendation of any product.
Energy audit demo questions · tick the ones you need
The pass tests are our reading of the cited provisions.
Nothing you tick is stored or sent.
What vendors say about ESOS
Which platforms say they support ESOS, in their own words?
The table opens on ESOS and shows what each vendor’s own site says, alphabetically, which ranks nothing. Many carbon and energy platforms handle ESOS data well; where a vendor’s pages are silent, ask in writing.
What vendors say about one regime · read 11 October 2026 and 30 September–1 October 2026
| Vendor | What its own site says | Published price |
|---|---|---|
| Altruistiq | No claim found on the pages we read | Enterprise level · TBD |
| ASUENE | No claim found on the pages we read | Enterprise level · TBD |
| Benchmark Gensuite | No claim found on the pages we read | Enterprise level · TBD |
| Briink | No claim found on the pages we read | Enterprise level · TBD |
| CarbonChain | No claim found on the pages we read | Enterprise level · TBD |
| Clarity AI | No claim found on the pages we read | Enterprise level · TBD |
| Climatiq | No claim found on the pages we read | Starter: Free; Data Pro €3,000 / year (single-user, scope 1, 2 and 3 emission factors; €5,000 / year for client consulting use); PCF Pro from €4,900 / year |
| Climatise | “One platform to run ESOS Phase 4 from start to finish”, through to MESOS notification and the action plan | Enterprise level · TBD |
| Compare Your Footprint | No claim found on the pages we read | Measure from £769 per year, billed annually (from £76/mo if billed monthly); Execute from £1,569 per year (from £156/mo monthly); Coordinate from £3,069 per year; 'Exact price depends on organisation size.' 14-day free trial, no credit card. |
| Coolset | No claim found on the pages we read | Enterprise level · TBD |
| Cority | No claim found on the pages we read | Enterprise level · TBD |
| Cozero | No claim found on the pages we read | Enterprise level · TBD |
| Datamaran | No claim found on the pages we read | Enterprise level · TBD |
| Dcycle | No claim found on the pages we read | Enterprise level · TBD |
| Deepki | No claim found on the pages we read | Enterprise level · TBD |
| Diginex | No claim found on the pages we read | Enterprise level · TBD |
| Diligent | No claim found on the pages we read | Enterprise level · TBD |
| Ecochain | No claim found on the pages we read | From €290 a month (Professional) and €640 (Business) on its German pricing page; the English page shows “Custom” |
| Ecologi | No claim found on the pages we read | PPN 006 Carbon Reduction Plan: 'Pricing starts at £3,499 + VAT'. Other plans not priced on the pages read; SME page offers 'a free account' (an Ecologi profile). |
| EcoOnline | No claim found on the pages we read | Enterprise level · TBD |
| EcoVadis | No claim found on the pages we read | Enterprise level · TBD |
| Emitwise | No claim found on the pages we read | Not sold standalone |
| Enablon | No claim found on the pages we read | Enterprise level · TBD |
| Envoria | No claim found on the pages we read | Enterprise level · TBD |
| Evotix | No claim found on the pages we read | Enterprise level · TBD |
| Green Project Technologies | No claim found on the pages we read | Enterprise level · TBD |
| Greenly | No claim found on the pages we read | Enterprise level · TBD |
| Greenomy | No claim found on the pages we read | Enterprise level · TBD |
| IBM Envizi ESG Suite | No claim found on the pages we read | Enterprise level · TBD |
| Ideagen | No claim found on the pages we read | Enterprise level · TBD |
| IntegrityNext | No claim found on the pages we read | Enterprise level · TBD |
| Intelex | No claim found on the pages we read | Enterprise level · TBD |
| IsoMetrix | No claim found on the pages we read | Enterprise level · TBD |
| Makersite | No claim found on the pages we read | Enterprise level · TBD |
| Manglai | No claim found on the pages we read | Enterprise level · TBD |
| Measurabl | No claim found on the pages we read | Free solution 'at no cost, in perpetuity' (tracking incl. Scopes 1–3, benchmarking, secure sharing); premium/paid upgrades (Navigate, Optimize, Comply) have no published price. |
| Microsoft Sustainability Manager | No claim found on the pages we read | US$4,000 (Essentials) or US$12,000 (Premium) per tenant, per month |
| Minimum | No claim found on the pages we read | Enterprise level · TBD |
| Net Zero Now | No claim found on the pages we read | Enterprise level · TBD |
| Normative | No claim found on the pages we read | Enterprise level · TBD |
| Nossa Data | No claim found on the pages we read | Enterprise level · TBD |
| Novata | No claim found on the pages we read | Novata for Companies: Manage 20K, Grow 50K, Lead 100K a year (currency not stated) |
| Novisto | No claim found on the pages we read | Enterprise level · TBD |
| One Click LCA | No claim found on the pages we read | Enterprise level · TBD |
| Optera | No claim found on the pages we read | Enterprise level · TBD |
| Oracle Fusion Cloud Sustainability | No claim found on the pages we read | Enterprise level · TBD |
| osapiens | No claim found on the pages we read | Enterprise level · TBD |
| Persefoni | No claim found on the pages we read | Persefoni Pro “completely free”, single user; Advanced by quote |
| Plan A | No claim found on the pages we read | Enterprise level · TBD |
| Planet Mark | For climate legislation support, including SECR and ESOS please see our bespoke services designed to meet your compliance requirements. | Enterprise level · TBD |
| Position Green | No claim found on the pages we read | Enterprise level · TBD |
| Pulsora | No claim found on the pages we read | Enterprise level · TBD |
| Quentic | No claim found on the pages we read | Enterprise level · TBD |
| Salesforce Net Zero Cloud | No claim found on the pages we read | Net Zero Cloud Growth £168,000 per organisation per year, billed annually, including one full CRM licence |
| Sami | No claim found on the pages we read | Enterprise level · TBD |
| SAP Sustainability Footprint Management | No claim found on the pages we read | Enterprise level · TBD |
| Sedex | No claim found on the pages we read | Sedex Supplier membership costs £224 or £374 per year, depending on the level of membership you choose. (Per site, billed annually; buyer membership not priced.) |
| Seedling | No claim found on the pages we read | TBC |
| ServiceNow Operational Sustainability Management | No claim found on the pages we read | Enterprise level · TBD |
| SimaPro | No claim found on the pages we read | Enterprise level · TBD |
| SINAI Technologies | No claim found on the pages we read | Enterprise level · TBD |
| Small99 | No claim found on the pages we read | Small99 Hero is free for all small businesses to get started to take climate action. |
| Sphera | No claim found on the pages we read | Enterprise level · TBD |
| Sweep | No claim found on the pages we read | Enterprise level · TBD |
| Tanso | No claim found on the pages we read | Enterprise level · TBD |
| Terrascope | No claim found on the pages we read | Enterprise level · TBD |
| Trace | No claim found on the pages we read | Enterprise level · TBD |
| Unravel Carbon | No claim found on the pages we read | Enterprise level · TBD |
| Watershed | Names ESOS among the reporting it works on | Enterprise level · TBD |
| Workday (supplier sustainability) | No claim found on the pages we read | Enterprise level · TBD |
| Workiva Carbon | No claim found on the pages we read | Enterprise level · TBD |
| Worldfavor | No claim found on the pages we read | A free plan for suppliers responding to data requests; buyer plans by quote |
| Zevero | No claim found on the pages we read | Zevero Lite (Scope 1 & 2) starts from £1,500 / year; main plans (Essential, Leading, Premium) by quote; add-ons: Product Carbon Footprint starts at £500 / product; EPD from £10,000 / product; AI-powered ESG Reporting starting at £1,000; Decarbonisation Strategy from £2,000; B Corp Audit from £750. One-year minimum. |
Each cell is the vendor’s own description of itself, linked to the page it is on.
A missing claim is a question to put to the vendor in writing, not evidence that the product lacks the capability.
Reading a vendor’s ESOS claimExplore
Reading a vendor’s ESOS claim
Audit or data?
Does it produce regulation 27 outputs, or hold the energy data an assessor uses?
Reading a vendor’s ESOS claim
kWh and £
Both, for every opportunity, since 22 July 2026.
Reading a vendor’s ESOS claim
Next phase
Does it keep the baseline for the savings-achieved report?
For the board
Energy audit software, in one sentence
The audit is ours to sign, the assessor’s to judge and the software’s to calculate, so buy the tool that shows its working.
Takeaways
Five facts, then the next step
| Fact | Source |
|---|---|
| Regulation 27 sets the audit’s outputs: profiles, opportunities, £, kWh, payback, programme. | SI 2014/1643 reg 27 |
| The audit must cover at least 95% of total energy consumption. | reg 25(2) |
| A lead assessor is needed unless consumption is under 40,000 kWh or ISO 50001 covers it. | reg 21(3); reg 33 |
| Phase 4 qualifies on 31 December 2026 and complies by 5 December 2027. | reg 4 |
| Savings achieved and the action plan review are new in Phase 4. | SI 2026/701 |
Next: check whether your group qualifies on ESOS qualification, then use the coverage calculator above to find the sites your audit must reach.
Frequently asked
Energy audit software, answered
What is energy audit software?
Software that takes an organisation’s meter, bill and site data and helps produce an energy audit: an analysis of where energy is used, the opportunities to use less, and the costs, savings and payback of each.
In the UK the legal template is the ESOS energy audit in regulation 27 of the ESOS Regulations 2014.
What must an ESOS energy audit contain?
Regulation 27 requires it, so far as reasonably practicable, to analyse energy consumption and efficiency, identify ways to improve, and recommend measures that are reasonably practicable and cost effective.
For each opportunity it must give the organisational purpose, the energy saving category, costs and benefits in pounds, the annual reduction in spend and in kWh, and the payback period, and it must recommend an implementation programme.
Can software carry out an ESOS audit on its own?
No. ESOS needs a lead assessor from an approved register, unless total energy consumption is under 40,000 kWh or ISO 50001 covers total or significant consumption, and the assessment is signed off at board level.
Software organises the data and the record; the judgements and the sign-off stay with people.
How much energy does an ESOS audit have to cover?
At least 95% of total energy consumption, measured in energy units or energy spend, under regulation 25(2).
The figure was 90% until SI 2023/1182 changed it from 29 November 2023.
Who has to do an ESOS energy audit?
A large undertaking: one that employs at least 250 people, or has turnover over £44 million and a balance sheet over £38 million, together with its UK group.
For Phase 4 the qualification date is 31 December 2026 and the compliance date is 5 December 2027.
What is an energy consumption profile?
Regulation 27(3) defines it as a breakdown of the different ways energy is used by the activities and assets of the participant and, where appropriate, an analysis of variations in that use.
An audit that does not use one must say so to the scheme administrator and record the alternative method and why.
Is ISO 50001 an alternative to an energy audit?
Yes, where certification covers total or significant energy consumption.
The participant is then treated as having met the duties to appoint a lead assessor, carry out the audit and produce the ESOS report; a notification of compliance is still required.
Partial coverage relieves only the certified part.
What happens if we do not carry out an energy audit?
Regulation 45 provides a penalty of £50,000, or such lesser amount as the compliance body decides, plus up to £500 for each working day until the breach is remedied, capped at 80 working days, and the penalty may be published.
Do audit savings have to be measured with IPMVP?
No UK rule requires IPMVP.
It is a voluntary protocol from the Efficiency Valuation Organization with four options for determining savings.
Phase 4 does require the savings achieved from earlier measures to be reported in kWh, so a consistent measurement method helps.
Is a Display Energy Certificate still an ESOS route?
No. SI 2026/701 removed Display Energy Certificates and Green Deal Assessments as compliance routes from 22 July 2026; data collected for them can still feed an ESOS report, but it cannot replace the audit.
Does energy audit software help with SECR?
The same kWh data feeds both.
SECR is an annual disclosure in the directors’ report and ESOS is a four-yearly audit, so software that holds one dataset and cuts it to both periods saves re-keying.
Has this site tested any energy audit software?
No. This page is built from the ESOS Regulations and the Environment Agency’s guidance, each cited to its provision.
The vendor table shows only what each vendor says about ESOS on its own site, alphabetically.
Sources
Primary sources
Every test on this page traces to the provision listed here.
Vendor statements are each vendor’s own, linked in the table.
Checked against 18 sources fromlegislation.gov.ukEnvironment AgencyGOV.UK (Environment Agency)ISEPISOEfficiency Valuation Organization
- legislation.gov.ukESOS Regulations 2014 (SI 2014/1643), regulation 27 — identification of energy saving opportunities
What an energy audit must analyse, identify, recommend and estimate.
- legislation.gov.ukSI 2014/1643, regulation 25 — significant energy consumption
The audit must cover at least 95% of total energy consumption (90% before 29 November 2023).
- legislation.gov.ukSI 2014/1643, regulation 25C — energy intensity ratios
At least one ratio for each organisational purpose with consumption.
- legislation.gov.ukSI 2014/1643, Schedule 1 — meaning of large undertaking
At least 250 employees, or turnover over £44m and balance sheet over £38m.
- legislation.gov.ukSI 2014/1643, regulation 4 — compliance periods and dates
Phase 4: qualification date 31 December 2026, compliance date 5 December 2027.
- legislation.gov.ukSI 2014/1643, regulation 21 — lead assessor
No lead assessor where total energy consumption is less than 40,000 kWh.
- legislation.gov.ukSI 2014/1643, regulation 22 — total energy consumption and the reference period
12 consecutive months beginning no more than 12 months before the qualification date.
- legislation.gov.ukSI 2014/1643, regulation 12 — approved registers
Lead assessors on registers meeting PAS 51215.
- legislation.gov.ukSI 2014/1643, regulation 34A — the ESOS action plan
Measures, dates and estimated savings in kWh, or a nil statement.
- legislation.gov.ukSI 2014/1643, Part 8 — civil penalties
Failure to carry out an energy audit, and the other four penalties.
- legislation.gov.ukESOS (Amendment) Regulations 2026 (SI 2026/701)
In force 22 July 2026: savings achieved in kWh, the action plan review, DECs and GDAs removed.
- Environment AgencyHow to comply with the Energy Savings Opportunity Scheme (ESOS) phase 4
The regulator’s guidance, 30 July 2026.
- GOV.UK (Environment Agency)Energy savings opportunity scheme (ESOS): find out if you qualify and how to comply
The ESOS hub, rewritten for Phase 4 on 2 September 2026.
- Environment AgencyManage energy saving opportunities reporting (MESOS)
Where notifications, action plans and progress updates are submitted.
- ISEPESOS lead assessor register
One of the approved registers; check the assessor before appointing.
- ISOISO 50001:2018 Energy management systems
The alternative compliance route where certification covers total or significant consumption.
- Efficiency Valuation OrganizationInternational Performance Measurement and Verification Protocol (IPMVP)
Four options for measuring savings; voluntary, not a UK legal requirement.
- Department for Energy Security and Net ZeroStreamlined Energy and Carbon Reporting regulations: evaluation
What compliers said annual reporting did and did not change.