Many companies are confused by ESOS compliance and the ESOS energy audit. So, we’ve created a short guide with the information a business needs to understand ESOS and the importance of an ESOS energy audit.
What is ESOS?
ESOS stands for Energy Savings Opportunity Scheme. This is a mandatory energy assessment scheme for large businesses in the UK that have 250 or more employees or have an annual turnover of more than €50 million and an annual balance sheet total of more than €40 million.
Who Runs the ESOS?
The ESOS is a scheme by the UK government that is run by the Environment Agency. Each country of the UK has different regulatory bodies that handle ESOS compliance and enforcement:
- England: the Environment Agency
- Wales: Natural Resources Wales
- Scotland: the Scottish Environment Protection Agency
- Northern Ireland: the Northern Ireland Environment Agency
How Many Businesses in the UK are in the ESOS?
Recent estimates from the Department for Business, Energy & Industrial Strategy (BEIS) show that about 11,900 UK businesses are required to become compliant with the ESOS.
Does ESOS Apply to Not-for-Profit Organisations?
Yes, non-profits can still meet the definition of a large organisation (as outlined above). Charities, trusts, and unincorporated associations may also meet the criteria.
Which UK businesses qualify for ESOS?
If a business has to comply if they have 250 or more employees or meets the financial thresholds (turnover over £44 million and a balance sheet above £38 million).
It’s required for Higher Education Institutions that are large enough to meet ESOS qualification criteria and self-declare as in the private sector.
However, non-profit corporate entities and universities that are almost completely funded by private sources and care homes are not considered public bodies. These all need to participate in ESOS if they meet the qualifications.
Identifying the Key ESOS Phase 3 Milestones
The ESOS Phase 3 compliance periods last for four years. The qualification date for ESOS Phase 3 is 31 December 2022.
Qualifying businesses need to complete their ESOS audit or use another route to compliance and notify the Environment Agency online of compliance by 5 December 2023.
Identifying the key ESOS Phase 4 milestones
The ESOS Phase 4 compliance period last for four years. The qualification date for ESOS Phase 4 is 31 December 2026.
Qualifying businesses need to complete their ESOS audit or use another route to compliance and notify the Environment Agency online of compliance by 5 December 2027.
What are the ESOS Regulations?
The Energy Savings Opportunity Scheme Regulations 2014 – ESOS Regulations is the UK government’s method to implement the requirements of Article 8 of the EUs’ Energy Efficiency Directive (2012/27/EU).
ESOS is the mandatory energy audit and energy efficiency identification scheme for large organisations and their corporate groups. The objective of ESOS is to increase energy efficiency, improve business profits and competitiveness, and put an end to climate change.
Corporate Grouping for ESOS Qualification and Participation
When a large organisation meets the ESOS qualification requirements, all UK entities within that corporate group (those with the same UK parent company) need to take part in ESOS.
If there is more than one UK parent company sharing the same overseas parent company, each needs to form one participant and notify the Environment Agent separately about compliance, and this should include all subsidiaries within the same corporate group.
However, if there is more than one UK parent with the corporate group, the highest UK parent groups can choose to come together and comply under the same notification. In this case, each parent company should agree in writing to participate together, and copies of the agreement must be kept within the evidence pack.
How Often Should an ESOS Audit Be Done?
If your business falls under ESOS, you must complete an energy assessment once every four years.
For ESOS Phase 4, this means:
- You must assess 12 consecutive months of energy use
- That 12‑month period must include 31 December 2026
- The ESOS audit can be carried out any time before the deadline
- Your final compliance submission must be completed by 5 December 2027
In practice, most businesses will use energy data from 2026 and complete their audit during 2026 or 2027, as long as it is submitted before the deadline.
When can the Phase 4 ESOS audit be carried out?
The ESOS audit itself can be completed at any point during the Phase 4 compliance period, which runs from 6 December 2023 to 5 December 2027.
As with previous phases, the timing of the audit is flexible, but the energy consumption data used must relate to the chosen 12‑month reference period and meet the qualification rules above.
Routes to Compliance
ESOS Phase 4 participants can choose one or more routes to compliance that cover a minimum of 95% of their total energy consumption, as outlined below:
- ISO 50001 certification
- ESOS audit
For ESOS Phase 4, Display Energy Certificates (DECs) and Green Deal Assessments are no longer accepted as routes to compliance.
If you choose to comply with ESOS completely or partially using ISO 50001 certification, the certificate must be UKAS‑accredited and valid on the Phase 4 compliance date (5 December 2027). Where a valid ISO 50001 certification is used, a separate ESOS audit is not required, although an ESOS compliance notification must still be submitted.
Why Use Us for Your ESOS Compliance and Energy Audit Requirements?
Planet Mark provides a credible and practical route to ESOS compliance, underpinned by more than 40 years of combined experience in energy management and sustainability. Our approach supports organisations through the ESOS process with clear structure, expert guidance and a strong understanding of regulatory requirements, ensuring audits are both compliant and commercially relevant. We recognise the budget pressures many businesses face and offers the flexibility to spread the cost of ESOS support over two years, helping to reduce financial strain while maintaining a high-quality service.
This combination of long-standing expertise, structured delivery and cost-effective options makes Planet Mark a trusted partner for organisations looking to meet ESOS obligations efficiently and with confidence. Our methods help you significantly reduce the associated costs and time spent on the ESOS audit, and it works to ensure that your ESOS compliance is completed on time.
If you’d like more information about our ESOS compliance & Energy Audit requirements, book your free health check today.
