ISO 50002 energy audit support for savings you can rank, fund and prove.

What it is

What is ISO 50002 and what is it used for?

ISO 50002 is the international standard for energy audits. Part 1 sets general requirements, with guidance, for how an audit is planned, how data are collected and measured, how the site is visited, how opportunities are analysed and ranked, and what the report must contain. It applies to buildings, processes, systems and transport, and ISO describes three levels of depth: a walk-through audit, a detailed survey and analysis, and a comprehensive engineering analysis.

Its value is comparability: audits run to one method, with the boundary and level agreed in advance, produce findings a finance director can compare and fund.

ISO 50002-1 can support the energy review that ISO 50001 requires, or it can be used on its own, for example to meet a customer request or to plan capital spending on energy efficiency.

Current edition. ISO 50002-1:2025, published in June 2025, replaced the withdrawn ISO 50002:2014. Part 2 (buildings) and Part 3 (processes), published the same month, add sector guidance. No certificate is issued against ISO 50002, so there is no transition period; specify new audits to the 2025 edition. ISO 50001, the EU Energy Efficiency Directive and ESOS

Who it is for

Who needs an ISO 50002 energy audit?

Any organisation that wants to know where it can save energy and what each saving is worth. Four situations bring organisations to Sterling:

• A customer or investor asks how you manage energy. Buyers and sustainability reviews expect a recognised audit method behind any reduction claim.
• A tender or funding application needs an audit report. Funding programmes often want audit findings first, and the method and auditor's competence must hold up.
• A regulation requires periodic energy audits. Each regulation sets its own scope, auditor and reporting rules; your legal advisers confirm what applies.
• A group company is building an ISO 50001 system. A structured audit gives the energy review measured data and ranked opportunities from the start.

Requirements

What are the main ISO 50002 requirements?

ISO 50002-1 is organised around three sets of requirements: principles for the auditor, the steps of the audit itself and the competence of the people who carry it out. Informative annexes add guidance on use, on applicability to other International Standards and on sampling. The list below is a plain-language summary at title level; the standard itself governs.

• Principles of energy auditing: competency, confidentiality, objectivity, access to equipment, resources and information, an evidence-based and risk-based approach, and communication.
• Planning: agree the objectives, scope, boundary, audit level, timing and information needs before any fieldwork.
• Opening meeting: confirm the plan, contacts, access and safety arrangements with the organisation.
• Data collection and measurement plan: gather consumption and operating data and decide what must be measured, where, how and for how long.
• Site visit: observe how energy is actually used and verify the data against real operation.
• Analysis: establish current energy performance, then identify, evaluate and prioritise improvement opportunities, now including decarbonisation options such as renewable energy.
• Reporting and closing meeting: present the findings, the ranked opportunities and their basis, and agree next steps.
• Competence of the energy auditor: generic and energy-specific competence, and the additional competence of a lead energy auditor.

Audit process

How is an ISO 50002 energy audit carried out?

The audit follows the sequence ISO 50002-1 sets out, carried out by your own competent team or an external energy auditor you appoint, with Sterling's consultants alongside to hold the method and connect findings to decisions.

1. 01
   Plan the audit.Agree why the audit is needed, the boundary, sites and energy types, the level of detail, the auditor and the timetable.
2. 02
   Collect the data and set the measurement plan.Hold the opening meeting, gather invoices, meter readings and operating data, and decide where extra measurement is needed.
3. 03
   Visit the site.Observe equipment, controls and operating practice, take the planned measurements and check the data against what really happens.
4. 04
   Analyse and rank the opportunities.Establish current performance, identify options, evaluate savings, costs and risks, and put the actions in priority order.
5. 05
   Report and act.Deliver the report, hold the closing meeting, and move the chosen actions into an owned, dated plan, or into the ISO 50001 energy review.

Check the route before you sign. No certification body certifies an organisation to ISO 50002, so be wary of anyone offering an "ISO 50002 certificate". Ask instead for the auditor's competence against the standard's competence requirements, the proposed level and boundary, and a sample report. Where a regulation requires the audit, confirm which auditor qualifications the regulator accepts. ISO 50001, the EU Energy Efficiency Directive and ESOS

Cost

How much does an ISO 50002 energy audit cost?

The effort depends on what the audit must answer: a walk-through of one office and an engineering analysis of several plants are different work. Our proposal names each component and states everything that is included.

Timeline

How long does an ISO 50002 energy audit take?

Duration follows the level and the boundary. As an estimate, most audits run from about one to four months between planning and the closing meeting; a comprehensive engineering analysis across several sites can take longer, especially where measurement must cover different operating conditions.

Your engagement

What your ISO 50002 engagement includes

Your engagement covers the method before the audit and the follow-through after it.

• Audit scope and specification

  Objectives, boundary, level and auditor competence set out against ISO 50002-1, ready for internal use or a tender.

• Data readiness

  Invoices, meter data and operating records organised, with the gaps the measurement plan must close.

• Effivity ISO & GRC software

  Audit records, opportunities and actions in one workspace, included with the engagement at no additional cost.

• Training for everyone

  Internal auditor training, as applicable to your standard, and preferential Sterling Academy access, including complimentary awareness training for your people as part of the engagement.

• Findings review

  The report tested against the method: are savings, costs and assumptions stated and traceable?

• Action plan and ISO 50001 link

  Chosen actions given owners, dates and verification, and fed into the energy review where an EnMS exists or is planned.

Sterling OS™ sets the support level. Design™ is guided: we give the method, templates and reviews while your team runs the audit work. Drive™ is managed: our consultants coordinate the audit and its follow-through with your people. You choose one, not both. After the audit, Sustain™ keeps the actions and repeat audits on schedule, and Automate™ is Effivity.

ISO 50002-1 carries no certificate, and Sterling does not certify, accredit or validate energy audits.

Often combined with

Standards organisations pair with ISO 50002

• EMASEMAS registration explained: requirements, the validated environmental statement, the verifier and Competent Body route, cost factors and all-inclusive support.
• FSC and PEFC chain of custodyFSC and PEFC chain of custody certification and requirements: FSC-STD-40-004 V3-1, PEFC ST 2002:2020, the audit route and cost factors, with Sterling.
• GHG ProtocolGHG Protocol inventory consulting: scope 1, 2 and 3 emissions on boundaries and methods an outsider can test, ready for independent verification.
• ISCC PLUSISCC PLUS certification for circular and bio-based materials: requirements, mass balance, ISCC HUB registration, standalone documents and an all-inclusive plan.
• ISO 14001ISO 14001 certification consulting: aspects, impacts and compliance obligations controlled, with support until an accredited body certifies you.
• ISO 14005ISO 14005 implementation guidelines: build your environmental management system in phases, measure maturity and reach ISO 14001 certification at your own pace.