ISO 500017 min read
ISO 50001 vs energy audit: what is the difference?
An energy audit analyses your energy use once. ISO 50001 turns energy performance into a routine. Here is how they differ and when you need which.
By Michael Schwarz, Lead auditor ISO 9001 and 14001, SICE
An energy audit is a one-off analysis of where your business uses energy and which measures would reduce it. ISO 50001 is a management system standard that makes energy performance a permanent task, with responsibilities, targets and records.
The two are often confused because both involve the word audit and both deal with energy. They answer different questions. The audit says what is happening and what you could change. The standard describes how your company keeps managing it after the report is filed.
What an energy audit is
An energy audit examines the energy use of a building, a production process or a whole company. An auditor, internal or external, collects consumption data, walks through the site, measures where needed and compares the findings with possible improvements.
The result is a report. It lists the main energy flows, the biggest consumers, a set of measures and an estimate of savings and payback for each. The method is described in standards such as ISO 50002 and EN 16247-1.
An audit is a snapshot. It is valid for the period it covers. What happens afterwards depends entirely on whether someone in your company picks up the measures and follows them through.
What ISO 50001 is
ISO 50001:2018 specifies an energy management system. It follows the same high level structure as other ISO management system standards, so it is built from clauses 4 to 10:
- 4 Context of the organization: scope of the system, interested parties, boundaries.
- 5 Leadership: energy policy, top management commitment, roles and responsibilities.
- 6 Planning: risks and opportunities, the energy review, energy baselines, energy performance indicators, objectives and action plans.
- 7 Support: resources, competence, awareness, communication, documented information.
- 8 Operation: operational control of significant energy uses, design and procurement decisions.
- 9 Performance evaluation: monitoring and measurement, internal audit, management review.
- 10 Improvement: nonconformities, corrective action, continual improvement of energy performance.
The standard does not set a savings target for you. It requires that you know your significant energy uses, set your own targets, measure against a baseline and act when results fall short.
The differences side by side
| Energy audit | ISO 50001 | |
|---|---|---|
| Nature | Analysis at a point in time | Management system that runs continuously |
| Main question | Where do we use energy and what can we save? | Who manages energy, how, and how do we know it improves? |
| Result | Report with measures and estimated savings | System with policy, baseline, indicators, objectives, reviews |
| Effort | Concentrated in the audit period | Spread across the year, owned by named people |
| Proof towards customers | An internal or consultant document | A certificate that a third party can verify |
| What happens next | Up to you | Built into the system through review and improvement |
How they work together
The two are not rivals. Clause 6 of ISO 50001 requires an energy review: you must analyse your energy use, identify the significant energy uses and find opportunities for improvement. An energy audit is a good way to produce exactly that. Many companies run an audit first, then build the management system around its findings.
The reverse also works. A company with a running energy management system already has clean consumption data, defined indicators and a list of planned measures. A later audit becomes quicker and cheaper because the auditor does not start from zero.
One difference matters in practice. ISO 50001 covers the review, but it does not produce a formal audit report in the sense of ISO 50002 or EN 16247. If a rule or a funding programme asks for that report specifically, the management system alone will not replace it.
Which one does your business need?
Start from the request in front of you, not from the standard.
An energy audit fits if
- you do not yet know where your energy goes and need a starting point;
- a grant, subsidy or financing programme asks for an audit report;
- a legal duty applies to your company and names the audit;
- you operate a single site and want a list of concrete measures.
Some countries oblige larger companies to carry out energy audits at fixed intervals, and in some cases a certified energy management system counts as an alternative. Whether this concerns you depends on your country and your company size. Ask the responsible authority before you decide.
ISO 50001 fits if
- a supplier questionnaire or tender asks for an ISO 50001 certificate;
- energy is a large cost item and you want savings to last;
- you have several sites or shifts and need one common way of working;
- you want a document your purchasing department can send to customers without a cover letter.
An audit report cannot answer a question that asks for a certificate. It is an internal document that the customer has to trust on your word. A certificate with a verification page is checked in a minute.
Smaller companies sometimes assume the standard is built for industrial plants. It is not. A scope of one office building or one workshop is valid, and the effort scales with the number of significant energy uses. The guide to ISO certification for small and medium businesses explains how this looks in practice.
The classic route and the alternative
The classic route to an ISO 50001 certificate involves an on-site audit by a certification body. It suits companies whose customers or authorities explicitly require that form, and it takes planning, travel and audit days.
Online self-assessment is a different route to a certificate. You answer structured questions about how your company manages energy, and the answers are reviewed before anything is issued. If you want to understand how this differs from the classic route, the page on ISO certification without an audit goes through it step by step.
Checklist: before you choose
If most boxes point to a customer asking for proof, the certificate is the faster answer. If they point to a lack of knowledge about your own consumption, start with the audit.
Where Zertify fits
Zertify issues ISO certificates based on an online self-assessment. There is no on-site audit. You answer the questions for ISO 50001 in your own time and describe how your company handles energy policy, baselines, indicators, objectives and reviews.
A member of the SICE Certification Board reviews every assessment. After a passed assessment and payment, the certificate is issued within 4 hours by G6 Agency AG under licence from SICE. It comes as a PDF with a QR code that leads to a public verification page, so a customer or purchasing department can check it themselves.
The certificate is valid for three years and is confirmed each year with a short online re-audit, which runs as a yearly subscription. The pricing page shows the current model.
Zertify does not replace an energy audit report where a rule or a funding programme names one. It answers the other question: can you show a third party that your company manages energy in a structured way? When you are ready, you can start the assessment. If some of your answers are weak, you will see it there before anyone else does.
A sensible order for most small companies
Companies with little knowledge of their consumption usually do best in three steps. First collect meter data for a year. Then run an audit, or a simplified internal review, to find the biggest consumers. Then document how you manage them and certify the system.
Companies that already know their numbers can skip the first steps. If your energy bills are tracked, your main consumers are known and a customer is waiting for a certificate, you can go straight to the assessment and use the results to see where the system still has gaps.
Frequently asked questions
Is an energy audit the same as an ISO 50001 audit?
No. An energy audit analyses energy use and proposes measures. An ISO 50001 audit or assessment checks whether your management system meets the requirements of the standard. The first produces a list of savings, the second a statement about how you manage energy.
Does ISO 50001 replace an energy audit?
Not automatically. The standard requires an energy review, which analyses your energy use, but this is not the same as a formal audit report under ISO 50002 or EN 16247. Whether a certified system can stand in for an audit depends on the rule or programme that applies to you, so check with the responsible authority.
Do I need an energy audit before ISO 50001?
No, it is not a prerequisite. You must carry out an energy review as part of the system. An audit is one good way to do that, particularly if you do not yet know your significant energy uses.
Can a small business get ISO 50001?
Yes. You define the scope, for example one site or one building, and the effort follows the number of significant energy uses. Small companies often certify when a customer or tender asks for it.
How long is a Zertify ISO 50001 certificate valid?
Three years. It is confirmed each year with a short online re-audit, which runs as a yearly subscription.
