ESOS Phase 4 Starts on 31 December: Turn Your Energy Audit into Real Savings
ESOS Phase 4 begins with a date, not a deadline
On 31 December 2026, every large UK organisation needs to check whether it qualifies for Phase 4 of the Energy Savings Opportunity Scheme (ESOS). The compliance deadline is not until 5 December 2027, so it is tempting to leave it until next year.
That would be a missed opportunity. Phase 4 asks a sharper question than earlier phases: not just where you could save energy, but what you have actually saved. Organisations that start now can arrive at their Phase 4 report with measured savings to show, rather than another list of recommendations.
Who qualifies, and the dates that matter
ESOS applies to large undertakings and their UK group. You are in scope for Phase 4 if, on 31 December 2026, your organisation (or any UK company in your group) has 250 or more employees, or an annual turnover above £44 million and a balance sheet above £38 million.
The Environment Agency published its Phase 4 guidance on 30 July 2026, following amendment regulations that came into force earlier that month. Qualification can be complex for groups, so confirm your position with your ESOS lead assessor or compliance adviser.
Phase 4 asks what you did with the last audit
For many organisations, past ESOS audits have produced sensible recommendations that never left the report. Budgets were tight, the payback looked uncertain, or nobody owned the next step.
Phase 4 makes that harder to leave unaddressed. Reports must now set out the energy savings actually achieved since the previous phase, and review measures from earlier action plans that were not carried out, with the reasons why. Your board signs off on that account.
At today’s prices, an unimplemented recommendation is also a cost. Business electricity contracts renewing this winter are significantly more expensive than a year ago, so every kWh identified in an audit and left in place is worth more than it was when the audit was written.
Turning findings into measured savings
The measures that serve ESOS best are the ones that deliver a verified saving quickly, without disrupting operations. That is what the patented enPact suite is built to do.
The patented enPact FilterPro is a site-wide electrical power alignment device, installed at your electrical incomer. It reduces the losses that build up across inductive loads such as motors, compressors and pumps. It delivers up to 18% off total site electricity, with a guaranteed saving typically around 6-7%, set after a baseline load survey.
The patented enPact Refrigeration & Cooling system fits to fridges, freezers, cold rooms, chillers and air conditioning. It adapts compressor cycles to real-time temperature data, so compressors run less while holding the same set temperature. It typically saves 20-45% on refrigeration loads, with a 20% guaranteed minimum.
The two work together and the savings add up rather than overlap. One of the world’s largest foodservice distributors has achieved 22% across refrigeration, cooling and site-wide electrical.
Why this fits ESOS reporting:
- Measured, not modelled. Every installation is monitored, so you have site-level data on savings achieved, ready for your Phase 4 report.
- Retrofit, with minimal disruption. enPact Refrigeration & Cooling fits with no disruption to the host equipment; enPact FilterPro needs only a short, planned electrical shutdown. Installation is carried out by our approved distributor partners.
- A guarantee built around your payback. The guaranteed saving sets the payback period. If verified savings fall short over that period, we optimise the system at our own cost first; if a shortfall remains, we reduce the project cost so your payback still lands where the guaranteed saving would have put it.
Five things to do before 31st of December
- Confirm whether you qualify for Phase 4, checking every UK company in your group.
- Complete your Phase 3 progress update by 5 December, if you took part in Phase 3.
- Dig out your last ESOS report and list the recommendations that were not implemented, and why.
- Re-price those recommendations at your next contract rate, not the rate in the original report.
- Start measuring now. The earlier a measure is installed and monitored, the more verified savings you will have to report by December 2027.
ESOS Phase 4 is a reporting obligation, but it is also a prompt to act on savings you already know are there. If you would like to know what the patented enPact suite could deliver across your estate, our team will start with a site survey and turn the ranges above into your own guaranteed figure.
Get in touch: call +44 (0)1642 049024 or email enquiries@emissis.com
