Although the compliance deadline for ESOS Phase 4 is not until 2027, many large organisations are beginning to plan their strategy. If past phases are anything to go by, 2027 will see a sharp increase in demand for qualified assessors, energy audits, and compliance support — creating bottlenecks, rising costs, and unnecessary stress for late movers.
Undertakinggoog quality energy audits now also enables you to identify and implement early savings that will help with future compliance costs.
Preparing now isn’t just about avoiding the rush. It’s about turning compliance into commercial advantage.
A Quick Refresher: What Is ESOS?
The Energy Savings Opportunity Scheme (ESOS) is a mandatory energy assessment scheme
ESOS applies to organisations that have a UK-registered company that meets either or both of the following criteria:
- Employ 250 or more people (including part-time)
- Have an annual turnover >£44million and a balance sheet >38million
Organisations that are part of a group or have foreign ownership are still required to take part if one of the UK subsidiaries meets the criteria. There are exceptions, mainly if income comes exclusively from public funding.
As a mandatory scheme, failure to comply can lead to significant fines and reputational damage.
ESOS requires the appointment of a registered Lead Assessor and for energy to be assessed, audited and recommendations signed off by a director. The results are notified to and can be audited by the scheme regulator.
Why 2027 Will Be Busy
There are several reasons why demand for ESOS support is expected to spike:
1. Stricter Reporting Requirements
Recent updates to ESOS have increased the level of detail required and scrutiny by the regulator. This can mean audits take longer and require more internal coordination.
2. Limited Assessor Capacity
The number of Lead Assessors had reduced in the last phase and so inevitably as deadlines approach, availability shrinks — and fees often rise.
3. Competing Regulatory Deadlines
Energy and carbon reporting obligations are increassing for some organisations. Businesses delaying ESOS until 2027 may face clashes with financial year reporting, budgeting cycles, and other compliance programmes.
The Case for Conducting Energy Audits Early
The core requirement of ESOS is the auditing of energy use to identify savings.
Carrying them out early will avoiding the compliance rush and lack of capacity/increased prices. This will allow for better budgeting and spreading costs over a number of financial years.
But the main advantage is that a well planned and executed energy auit is the early identification of opportunities to save cost. For example:
- Inefficient heating and ventilation systems can be adjusted giving immediate savings
- Poor insulation or building fabric issues can be addressed before next winter
- Compressed air leaks can be addressed during planned shutdowns
- Transport fuel inefficiencies can have budgets allocated earlier
Implementing improvements ahead of Phase 4 means you could:
- Reduce energy bills immediately
- Improve operational resilience
- Lower exposure to volatile energy prices
- Allocate capex accordingly
- Show progress to stakeholders
- Align with net zero and ESG reporting
The Risk of Non-Compliance
The Environment Agency has enforcement powers, including financial penalties for non-compliance. Leaving preparation until the final months increases the risk of:
- Incomplete audits
- Missed coverage thresholds
- Delayed sign-off
- Administrative errors
Early audits provide time for correction and verification.
Practical Roadmap to Prepare for ESOS Phase 4
If you want to enjoy the advantages of early action, consider this roadmap:
1. Confirm Qualification Status
Assess whether your organisation will qualify/still qualifies under expected employee numbers or financial thresholds at the end of 2026.
2. Appoint an ESOS Lead Assessor Early
Engage an experienced and qualified Lead Assessor to guide scope, data requirements, and timelines.
3. Begin Data Collection
Put in place systems to gather data this year on a month by month basis to cover
- Utility/fuel data for every site, however small
- Transport fuel records
- Production/process energy data
- Building floor areas
4. Conduct Energy Audits
Start with high-consumption sites to identify quick wins. Your Lead Assessor will advise you.
5. Align With Decarbonisation Strategy
Use ESOS as a stepping stone toward broader sustainability goals.
Summary: The Strategic Advantage of Acting Early
Organisations that treat ESOS as a last-minute obligation often gain little more than a compliance certificate.
Those that act early gain:
- Lower operating costs
- Reduced carbon footprint
- Improved ESG performance
- Better investor confidence
- Operational efficiency improvements
- Reduced exposure to energy market volatility
In a period where energy costs, regulatory scrutiny, and sustainability expectations continue to rise, early action is not just prudent — it’s commercially intelligent.
ESOS Phase 4 may feel distant, but from previous phases we know the compliance surge is real and capacity will start to reduce from the end of 2026. Businesses that begin energy aduits now will avoid the bottleneck, reduce risk, unlock tangible financial and environmental benefits and get a better overall deal.
The choice is simple; compete for assessors at the last minute — or turn early compliance into competitive advantage.
Talk to our ESOS experts about taking advantage of early ESOS services