ESOS Auditor Help Videos & FAQs

In order to prepare for the use of the ESOS Auditor tool certain information should be gathered in advance and decisions should be made as how your organisation will use the tool to ensure that your initial use of the software is as straightforward as possible.

The help videos, guidance notes and FAQs below have been produced to highlight the requirements of ESOS and to assist you in setting up and using the ESOS Auditor.

Once logged in, you can get instant help for each page by clicking the "Help" link at the top right.

If you require further help, please contact support:

Help Videos

System Set Up

Inputting Data

Checking Data


Frequently Asked Questions

Before you set up ESOS Auditor for the first time it is sensible to decide how you are going to run things internally within your organisation. Things to consider include:

Account Owner

  • who will purchase, set-up and undertake ongoing management of the
  • an internal member of staff or the external Lead Assessor

Organisation structure

  • particularly important if you are part of a group undertaking
  • please see our related help FAQ on this

Number of users required

  • you can request more at a later date on a pro rata cost if needed

What each users is going to be responsible for

  • what roles they will undertake
  • for what part(s) of the organisation
  • please see our related help FAQ on this

There are several user roles within the tool which should be considered and assigned (ideally in advance of initial set up) based on how you intend to use the software. They relate to each other as follows:

User Role Software Access Functionality User Suggestions
Account Owner
  • Organisation Setup
The person who initially sets up the account. This is the only person who has access to ‘Organisation Set Up’ part of the tool. Enters the organisation hierarchy, along with address details, but also has access to all other parts of the tool. 1 per organisation
Account Administrator
  • Settings
Adds / edit / deletes users, changes user access and user roles. Has access to the ‘Settings’ part of the tool. 1 or 2 needed per organisation
Data Manager
  • Input Energy Data
Collects and collates Energy data. Provides meter readings and data input for Buildings and Processes. Provides evidence in the form of photographs / energy bills / calculations. Can also enter supply energy or cost data and evidence for Transportation. Has access to the ‘Input Energy Data’ part of the tool. Typically 1 per Building / Process / Transportation or per site/sub-group
Data Checker
  • Data Check
Audits 90% of data entered by the Data Manager(s). Accepts or rejects evidence from the Data Manager. Has access to the ‘Data Check’ part of the tool. Typically 1 per Group Company and/or 1 per entire organisation
ESOS Reporter
  • Report
Collates the Energy Savings Measures in preparation for reporting. Produces the ESOS reportage required for submission to the Board and the Environment Agency / SEPA etc. ESOS Reporters can also create reports at any level in the organisation’s hierarchy from a single company to the entire organisation. Could be the responsible Board Director for ESOS. Has access to the ‘Report’ part of the software. Typically 1 per Group Company and 1 per entire organisation

All the roles above can be set at any level of organisation hierarchy i.e. a Data Manager for Group Company 2 could provide metered data for that Group Company and any Companies underneath it in the hierarchy, and for any number of Buildings.

For example, you may wish to give the ESOS Lead Assessor both Data Checker & ESOS Reporter roles so that they can audit 90% of data entered by the Data Manager(s); accept or reject evidence from the Data Manager; and collate the Energy Savings Measures in preparation for reporting to the Board and the Environment Agency / SEPA etc. You will typically have one ESOS lead Assessor per Group Company and/or one per entire organisation.

If a corporate group contains at least one undertaking in the UK which meets the qualification conditions, its entire UK operation must take part in ESOS.

The rules are quite complex and you should make sure that you understand how your organisation complies before you start using ESOS Auditor, as this impacts on how you might wish to set up the software.

ESOS Auditor reports and provides access based on your organisation hierarchy. This structure, along with address details needs to be entered into the tool. You can have up to four ‘levels’ in your company hierarchy to take account of parent companies or sub-groupings that you want to use. This flexibility enables you to fit the software to the way your business is managed.

Organisational Tree

Below is some information from the Environment Agency guide, please read Sections 1.7-1.10 in full at Further advice can be obtained from the Environment Agency ESOS help desk:

The highest UK parent of a group is the undertaking which has no parent, or only has parents which are overseas undertakings. All subsidiary undertakings of that highest UK parent would, by default, be part of the same participant for ESOS.

By default the highest parent acts as the responsible undertaking – this means it will complete the ESOS Assessment and notify the Environment Agency of compliance for itself and subsidiary undertakings.

Another undertaking within the highest parent group can be chosen to act as the responsible undertaking provided all undertakings in the highest parent group agree this in writing, and keep this agreement.

Undertakings within a highest UK parent group can disaggregate from one another for the purposes of compliance with ESOS, provided they agree in writing with their highest parent. Undertakings that disaggregate will therefore report compliance as two or more separate participants.

If a corporate group contains overseas parent undertakings, the corporate group may consist of more than one highest UK parent group. In this instance, if one highest UK parent group is in scope of ESOS then every other highest UK parent group in the same global group must also participate in ESOS. However, the default is that in this circumstance each highest UK parent group will participate separately.

If the highest UK parent groups within the same corporate group wish to comply as one participant (to 'aggregate') all highest parents in those highest parent groups must agree in writing which of them is to be the responsible undertaking in relation to the participant’s compliance with the scheme.

For ESOS you are required to measure your total energy consumption across a 12-month period known as “the reference period”. When you first set up ESOS Auditor you will asked to specify what this is. It can be changed at a later date. The reference period must include the ESOS qualification date and end before the compliance date, for example.

Organisational Tree

In order to comply with ESOS you need to ensure an assessment of total energy consumption has been conducted, that 90% of the total energy consumption is compliant via ESOS audits or an alternative route to compliance, and that the data to evidence this work and its findings is recorded.

ESOS Auditor provides you with the data management and storage structure to do this in one online platform. It aids in:

  • measuring your total energy consumption (in either energy units (e.g. kWh) or energy expenditure (£) across buildings, transport and industrial processes plus evidencing with verifiable data)
  • identifying areas of significant energy consumption (90% or more)
  • ensuring areas of significant energy consumption are compliant via ESOS audits or an alternative route to compliance (ISO 50001 certification, Display Energy Certificates (DECs), Green Deal Assessments (GDAs))
  • collating, reviewing and prioritising energy saving opportunity measures identified by ESOS audits or alternative compliance routes
  • co-ordinating with your Lead Assessor and internal team
  • engaging with board level directors through automatically produced assessment finding reports
  • detailing all information needed to make your ESOS compliance notification
  • keeping an evidence pack for the compliance period to which it relates and the two subsequent compliance periods

ESOS Auditor uses the specified UK Government conversion factors ( to help you measure energy consumption in common units. We have also included the ability to add your own custom fuel types into the software if the fuel type or measurement unit you wish to use is not included as standard.

They will then be available to use in both the Energy Data and Batch Data sections once added.

The Batch Data section allows you to import information in bulk in the form of a spreadsheet .csv file. Template .csv files are provided to make the process as easy and simple as possible. If you have a large amount of data to add all in one go, or you are exporting information from another system this will probably be the best place to start.

For this route it is easier to add buildings and processes first, before supplies. If any records are rejected on upload they will be added to a .csv file that you can download to view and fix any problems, before uploading again.

We’ve included a wide range of fuel types as standard, but custom types can also be added by the Account Administrator if needed. This should be done before you start the Bulk Data upload process.

Once data has been uploaded you can review uploads undertaken in the List Batch sections. Then you can further edit and refine this information in the Energy Data section.

The Bulk Data section provides capabilities for Energy Supply, Building and Process Data. A capability for Transport is planned for the future.

When calculating your total energy consumption, you must use verifiable data where reasonably practicable. ESOS Auditor allows such ‘evidence’ documents to be uploaded to the system against the energy consumption being documented. For example; an electronic energy bill, scanned delivery note, photo of meter, or copy of a calculation outlining assumptions where no physical evidence was available.

Verifiable data is data you can prove, for example:

  • an invoice or delivery note
  • meter reading records and schedules for electricity or natural gas
  • stock records and readings for stored liquid, solid fuels and waste
  • automatic meter reading or smart and half hourly meter data outputs, for electricity and natural gas

If you can’t obtain verifiable data of energy use or spend you should:

  • explain why in your evidence pack
  • use a reasonable estimate derived through calculation (based on other verifiable data, if possible), and show how you got this figure
  • keep records in your evidence pack

You must keep the evidence pack for the compliance period to which it relates and the two subsequent compliance periods. It should include:

  • contact details of the participating undertakings and the responsible undertaking
  • details of any board level directors or equivalents who’ve reviewed the ESOS assessment findings
  • written confirmation from the director(s) to evidence that they reviewed the ESOS assessment
  • contact details of your lead assessor and the name of the approved register which they are a member of
  • written confirmation from the lead assessor to evidence that they signed off the ESOS assessment
  • the calculation for your total energy consumption
  • a list of your identified areas of significant energy consumption
  • details of the energy audits undertaken including the audit methodology used in your ESOS energy audits
  • details of the energy saving opportunities identified
  • details of the routes to compliance used to cover each area of significant energy consumption and where applicable evidence (e.g. certificates) of the alternative routes to compliance
  • written agreements to support any disaggregation or aggregation of group members
  • written agreements to support any alternative responsible undertaking chosen (other than the default highest UK parent)
  • reasons for using less than 12 months of data for the measurement of total energy consumption, if you couldn’t do this
  • reasons for using less than 12 months of data to support an ESOS energy audit, if you couldn’t do this
  • reasons for being unable to use verifiable data on energy use or energy expenditure to support your calculation of total energy use
  • the methodology you used for any estimates you’ve made for energy use or energy expenditure
  • justification, where applicable, where your lead assessor has not used an energy consumption profile in your audit of an area of significant energy use

All participants need to have their ESOS assessment signed off by an ESOS lead assessor. We have partnered with a number of approved professional bodies who run ESOS Registers to provide a range of linked services including training options, and exclusive ESOS Auditor software discounts.

You should select a lead assessor with the necessary skills and experience to help your business comply with ESOS. IES has partnerships with the following professional bodies. Please contact them directly if you need further information about their application processes and/or approved lead assessors on their registers.

A full list of approved registers of lead assessors can be found here

The Energy Savings Opportunity Scheme (ESOS) is an energy assessment and energy saving scheme established by the Energy Savings Opportunity Scheme Regulations 2014 (ESOS Regulations).

The scheme applies to large undertakings and groups containing large undertakings in the UK.

An undertaking, as defined in the Companies Act 2006, is:

  • a corporate body or partnership
  • an unincorporated association carrying on a trade or business, with or without a view to profit

You must take part in ESOS if your organisation qualifies as a large undertaking on the qualification date. The qualification date for the first compliance period was 31 December 2014.

A large undertaking is any UK undertaking that meets either one or both of the conditions below:

  • it employs 250 or more people
  • it has an annual turnover in excess of 50 million euro (£38,937,777*), and an annual balance sheet total in excess of 43 million euro (£33,486,489*)

You must also take part in ESOS if your undertaking is part of a corporate group which includes another UK undertaking that meets either of these conditions. Where a corporate group participates in ESOS, unless otherwise agreed the highest UK parent will act as a 'responsible undertaking' and be responsible for ensuring the group as a whole complies.

The definition of an undertaking includes an overseas company with a UK registered establishment which has 250 or more UK employees (paying income tax in the UK).

You are not required to participate in ESOS if:

  • your organisation is defined as a contracting authority by regulation 3 of:
    • The Public Contracts Regulations 2006 in England, Wales and Northern Ireland
    • The Public Contracts (Scotland) Regulations 2012 in Scotland
  • your undertaking is subject to an insolvency procedure
  • you do not meet the qualification criteria outlined in section 1.1.

Where you are part of a corporate group and only parts of the group fall into the categories above then the rest of the group will be required to participate in ESOS if they qualify.

If an undertaking only voluntarily complies with the Public Contracts Regulations 2006 or Public Contracts (Scotland) Regulations 2012 they will still need to participate in ESOS.

For more information see the Environment Agency Guide ( ) or contact the Environment Agency ESOS help desk:

* The equivalent pound sterling figures specified in brackets above were determined by the Environment Agency for the first compliance period based on the Bank of England daily spot exchange rate on 31 December 2014.

If you have an ISO 50001 energy management system that’s certified by an approved certification body and covers all your energy use (for the whole corporate group in the UK), this counts as your ESOS assessment. To be compliant:

  • the certification must remain valid at the compliance date.
  • the Energy Management System must cover all of the assets held and activities carried on by your organisation as at the qualification date.

If you don’t have an ISO 50001 energy management system which covers all your energy use, you must carry out an ESOS assessment.

ESOS participants may also be part of other energy management/reporting schemes, like:

  • the EU Emissions Trading System (EU ETS)
  • Climate Change Agreements (CCAs)
  • the CRC Energy Efficiency Scheme (CRC)
  • mandatory greenhouse gas (GHG) reporting for quoted UK companies.

Please note that simply being part of these other schemes does not automatically count as ESOS compliance for the energy covered by those regimes. You can use energy data you collect as part of your compliance with these schemes to calculate your total energy consumption for your ESOS Assessment but you are likely to have to do additional work to ensure you are also compliant with ESOS.

The scope of energy you must include in your total energy consumption under ESOS is broader than what’s covered by these mandatory and voluntary schemes. This means that it’s unlikely you’ll be able to calculate your total energy consumption based on what data you collect for these schemes alone. Run by NIFES Consulting, part of the INENCO Group. All of the information here is intended to be independent, helpful and useful. The Environment Agency published updated ESOS guidance on 17th February 2015 on behalf of all the scheme compliance bodies, namely Natural Resources Wales, Scottish Environment Protection Agency, Northern Ireland Environment Agency and Department of Energy & Climate Change (DECC) Offshore. This updated guidance supersedes DECC’s ESOS Guide published in June 2014.

  • the scope of the ESOS qualification criteria with respect to overseas undertakings and UK establishments
  • the application of ESOS to trusts
  • determination of corporate groupings
  • calculation of total energy consumption
  • auditing approach for the construction sector
  • notification requirements
  • the approach to site visits
  • the treatment of assets purchased or disposed of after the qualification date and before the compliance date
  • the extent of inclusion of transport energy
  • liability for compliance in cases of disaggregation
  • what records to keep in your evidence pack

Your environmental regulator is responsible for compliance and enforcement activities. Your registered office or principal place of activity (in the absence of a registered office) determines your regulator:

  • England – Environment Agency
  • Northern Ireland – Northern Ireland Environment Agency
  • Scotland – Scottish Environment Protection Agency
  • Wales – Natural Resources Wales
  • Offshore – DECC Offshore Oil & Gas Environment and Decommissioning

The Environment Agency is collating notifications from participants on behalf of all regulators. Use the online notification system ( \)to notify the Environment Agency that you are ESOS compliant.

We welcome requests for new functionality for ESOS Auditor. Please email us at with your suggestions.
Yes, in 2016 and beyond you can choose to access your data for only £10/month (£120 per year with 1 user access). For this you can keep a completed data set on the site to access anytime, but without the ability to edit it. A requirement of ESOS is that you must keep your evidence pack for the compliance period to which it relates and the two subsequent compliance periods. As each compliance period is 4 years, this can be as long as 12 years.
Yes in 2016 and beyond this will be possible.
Download Guide Further information can be obtained within the Environment Agency ESOS guide: