MESOS
The government service where a group notifies compliance, signed in through GOV.UK One Login.
On ESOS software and ESOS online.Software · a buyer’s guide to ESOS tools
ESOS software: the tools for Phase 4, and how to choose
ESOS software gathers a group’s energy data, holds its audits and action plan, and produces the evidence its lead assessor reviews before notification.
Only 3 vendors in this site’s registry name ESOS on their own pages, so this page also shows where the rest of the market does the work under other names.
MESOS, sign-in and the steps the law keeps human are on ESOS software and ESOS online.
Two pages, two jobs
Are you looking for MESOS, or for a tool?
Many people searching “ESOS software” want the government’s MESOS service, which is where the notification is made.
Everyone else wants a tool for the work before it: measuring total energy, running audits and keeping the evidence.
The first is covered on ESOS software and ESOS online; this page is about the second.
Searching
ESOS software
ESOS software
A tool
Software that measures energy, holds audits and the action plan, and builds the evidence pack.
On this page.The platforms
Which platforms say they support ESOS?
3 of the 73 vendors in this site’s registry name ESOS on their own pages, read 11 October 2026 and 30 September–1 October 2026, listed alphabetically.
Each line is the vendor’s own, linked to the page that says it.
United Kingdom
Climatise
Price: Enterprise level · TBD
United Kingdom
Planet Mark
Price: Enterprise level · TBD
Joined Alcumus in 2023; its site now places it in Veriforce’s UK supply chain division
Headquarters not stated on its site
Watershed
Names ESOS among the reporting it works on
Price: Enterprise level · TBD
3 vendors, alphabetically. Each line is the vendor’s own description, linked to the page it is on.
A vendor missing from this list may still do the work: put the question to it in writing.
The list is short because ESOS is counted in kilowatt-hours and is UK-only, so international carbon platforms rarely use the word.
Tools that measure and audit energy under other names are covered on energy monitoring software, energy audit software and energy management software.
Where ESOS work happensExplore
Where ESOS work happens
ESOS-named tools
3 vendors whose own pages name ESOS.
Where ESOS work happens
Energy monitoring
Meter and bill data in kWh: the total ESOS starts from.
From the list to three
How do you build an ESOS shortlist when few vendors use the word?
Start with the vendors that name ESOS, then widen the search by the jobs ESOS needs rather than its name.
Those jobs are a total of every form of energy for a 12-month reference period, audits that meet regulation 27, an action plan and progress updates under Part 6A, and an evidence pack under regulation 28.
The tool beside this text keeps vendors that also claim the other duties you tick, such as SECR, which shares the same meter data.
Ask your lead assessor which tools they already work with; the evidence pack is for them.
Your long list · from vendors’ own pages, read 11 October 2026 and 30 September–1 October 2026
Start: vendors whose own pages mention ESOS (3). Tick what else the same tool must serve.
3 of 3 vendors make every claim you ticked.
Alphabetical; the order ranks nothing. A claim is what a vendor says, not a test result.
Nothing you tick is stored or sent.
One group, start to finish
What does choosing look like for a group in Phase 4?
Group B is an illustration: a large undertaking on the 31 December 2026 qualification date, with thirty sites and a fleet.
Two sites already run an ISO 50001 system, which can cover their share of energy; the rest needs audits.
Because the same meters feed its SECR report, it ticks ESOS and SECR in the long-list tool and adds one energy monitoring platform its facilities team already uses.
Its lead assessor sets the test: can each tool export a coverage figure and an evidence pack she can review without logging in?
Group B, Phase 4Explore
Group B, Phase 4
Qualifies
A large undertaking on the qualification date, 31 December 2026.
Group B, Phase 4
Energy
Thirty sites, a fleet and a gas-heated warehouse estate.
Group B, Phase 4
Shortlist
Tools claiming ESOS and SECR, plus one energy monitoring platform.
In the demo
What should you ask in an ESOS demo?
Run the demo on one site’s real data and one month of the fleet.
Start with the total energy figure for your reference period: it decides coverage, and coverage decides how much auditing you buy.
This site has tested no products
The questions test what a tool does for ESOS; they score no one, and passing them is not an approval.
ESOS demo questions · tick the ones you need
The pass tests are our reading of the cited provisions.
Nothing you tick is stored or sent.
The Phase 4 clock
When should you buy to make the Phase 4 deadline?
Qualification date
31 Dec 2026Phase 4Notify by
5 Dec 2027Through MESOSVendors naming ESOS
3In this site’s registryThe reference period is 12 consecutive months that include 31 December 2026 and end on or before 5 December 2027, under regulation 22(5).
A tool bought in 2026 can hold that period’s data as it arrives; one bought late in 2027 has to load it in a rush.
The dates and routes are set out on ESOS deadlines.
Phase 4, in orderExplore
After you sign
How does a Phase 4 cycle run on a new platform?
- 01 / Energy01
- 02 / Coverage02
- 03 / Audits03
- 04 / Plan04
- 05 / Evidence05
No official timetable exists for setting up ESOS software; this order is this site’s, built from the provisions cited.
Buy ESOS software for the evidence pack your lead assessor needs, not for the dashboard.
The notification rests on that pack.
In short
ESOS software, in five facts
| Fact | What to do with it |
|---|---|
| 3 vendors name ESOS on their own pages | Widen the list with energy monitoring and audit tools. |
| MESOS is the government service | Notify there; analyse in your tool. |
| Notification is due by 5 December 2027 | Buy in 2026 so the reference period’s data lands in the tool. |
| A lead assessor reviews the evidence | Ask them which exports they need before you sign. |
| SECR uses the same meters | Pick a tool that cuts one dataset two ways. |
Next: check how MESOS and sign-off work on ESOS software and ESOS online, then take the demo questions to three vendors.
Frequently asked
ESOS software, answered
What is ESOS software?
Software that gathers a group’s energy data, measures it against the Energy Savings Opportunity Scheme’s requirements, and holds the audits, action plan and evidence.
The notification itself is made on the government’s MESOS service, which is covered on our ESOS software and ESOS online page.
Which software supports ESOS?
In this site’s registry, 3 vendors say on their own pages that they support ESOS, read 11 October 2026 and 30 September–1 October 2026: Climatise, Planet Mark, Watershed.
Energy monitoring and energy audit tools do much of the work without using the word; see those guides too.
Why do so few vendors mention ESOS?
ESOS is measured in energy, not emissions, and it is UK-only, so carbon platforms built for international markets rarely name it.
The work an ESOS tool does — consumption totals, profiles and savings in kWh — is often done by energy management and monitoring software instead.
What is the best ESOS software?
This site has tested no product and names no best.
Choose the tool that totals every form of energy for your reference period, shows audit coverage, holds the action plan and exports the evidence pack, on your own data.
When is the ESOS Phase 4 deadline?
The qualification date is 31 December 2026 and the notification is due by 5 December 2027, through MESOS, according to the Environment Agency’s Phase 4 guidance.
Does ESOS software replace the lead assessor?
No. ESOS requires a lead assessor on an approved register to review the assessment, and directors to sign it off.
Software holds and organises the evidence they review.
Is there official ESOS software?
The official service is MESOS, used to notify compliance.
It is not an analysis tool; the energy measurement and audit work happen before it.
Can ESOS software also do SECR?
Often, because both start from the same meter and bill data.
SECR wants emissions and kWh for the financial year in the directors’ report; ESOS wants kWh for a 12-month reference period, so the tool must cut the same data two ways.
Does ISO 50001 replace ESOS software?
An ISO 50001 certificate can be a compliance route for the energy it covers.
A tool that runs an energy management system is then doing ESOS work under a different name; check its coverage figure.
How long does ESOS software take to set up?
There is no official figure.
Allow time to list every meter and fuel, agree the reference period, and load the data; with a 5 December 2027 notification date, the purchase is best made in 2026.
Who owns the data in ESOS software?
You do, with the vendor as processor under a written contract.
UK GDPR sets what that contract must include; read the exit terms before signing.
Sources
Primary sources
Every requirement on this page traces to a provision listed here.
Vendor descriptions are cited to each vendor’s own page.
Checked against 16 sources fromlegislation.gov.ukGOV.UK (Environment Agency)GOV.UKISEPISOInformation Commissioner’s Office
- legislation.gov.ukEnergy Savings Opportunity Scheme Regulations 2014 (SI 2014/1643)
The scheme itself.
- legislation.gov.ukESOS Regulations, regulation 22
The Phase 4 reference period.
- legislation.gov.ukESOS Regulations, regulation 27
What an energy audit must contain.
- legislation.gov.ukESOS Regulations, regulation 28
The evidence pack.
- legislation.gov.ukESOS Regulations, Part 6A
Action plans and progress updates.
- legislation.gov.ukESOS Regulations, Schedule 1
Definitions used in the scheme.
- legislation.gov.ukESOS (Amendment) Regulations 2026 (SI 2026/701)
The 2026 amendments.
- GOV.UK (Environment Agency)Energy Savings Opportunity Scheme (ESOS)
The scheme hub.
- GOV.UK (Environment Agency)How to comply with ESOS Phase 4
Dates, compliance routes and the lead assessor.
- GOV.UK (Environment Agency)ESOS Phase 4 guidance, Appendix C
Advice for complying with ESOS.
- GOV.UKManage energy saving opportunities reporting (MESOS)
Where notifications are made.
- ISEPRegister of ESOS lead assessors
One of the approved registers.
- ISOISO 50001 Energy management systems
A compliance route under ESOS.
- legislation.gov.ukSI 2008/410, Schedule 7
SECR, which shares the meter data.
- Information Commissioner’s OfficeUK GDPR: what needs to be included in a processor contract
The terms that govern a vendor holding your data.
- GOV.UK (DESNZ)Government conversion factors for company reporting
For any emissions view of ESOS energy.