By Tim Polidori
Head of Construction, Focus Green · MSc in Building Surveying · MCIOB · NDEA
Most organisations are still focused on ESOS Phase 4, with a qualification date of 31 December 2026 and a compliance deadline of 5 December 2027. But ESOS runs in four-year cycles, so the next phase is already on the horizon. Based on that cycle, Phase 5 would be expected to use a qualification date of 31 December 2030 and a compliance date of 5 December 2031.
No Phase 5 regulations have been published. This article sets out how Phase 5 might look, based on the changes already made to ESOS and the reforms Government has said it is considering. Treat it as planning guidance, not a statement of the law.
Where ESOS is today
The 2023 amendments reshaped the scheme. Organisations now report more detailed energy and building data, and since Phase 3 they must publish an action plan setting out the energy-saving measures they intend to take, followed by annual progress updates. The Environment Agency has also shown it will enforce: it has penalised more than 160 organisations for non-compliance, as covered in our ESOS enforcement update.
That shift, from reporting opportunities to committing to and tracking actions, is the clearest signal of where Phase 5 is likely to head.
1. From audit to delivery
Government has previously consulted on making ESOS more action-focused, including the possibility of requiring some recommendations to be implemented. Phase 5 could build on the action-plan regime by expecting evidence that planned measures have actually been delivered, or by scrutinising progress updates more closely. Organisations whose Phase 4 action plans are vague may find that harder to defend later.
2. Net zero alignment
Earlier consultation proposals discussed aligning ESOS with net zero, for example by asking organisations to consider decarbonisation pathways and not just short-term savings. A future phase could expect audits to cover electrification, heat pumps, on-site generation and fabric improvements alongside quick wins such as controls and lighting.
3. Better data and possible metering expectations
Phase 4 already asks for more granular data. Phase 5 could go further, with greater emphasis on sub-metering, half-hourly data and consistent intensity metrics that allow year-on-year comparison. Organisations that install metering and monitoring now will be better placed whatever the final requirements.
4. Closer links with other regimes
ESOS sits alongside SECR, MEES, TM44 air-conditioning inspections and commercial EPCs. Government has signalled interest in reducing duplication between reporting schemes. Phase 5 could make more use of data already produced for these regimes, which rewards organisations that keep one coherent evidence base for their estate.
5. Assessor quality and enforcement
Lead assessor standards and Environment Agency audits are likely to remain central. With penalties already issued in previous phases, it is reasonable to expect continued enforcement, and potentially more scrutiny of the quality of audits and action plans, not only of whether a notification was submitted.
What to do now
The best preparation for Phase 5 is a strong Phase 4: accurate group boundaries, good data, a realistic action plan and honest progress updates. Our ESOS evidence pack guide explains what to keep. Treat measures in your action plan as projects with owners, budgets and dates, and track the savings so you can show results.
We support organisations through ESOS compliance and beyond. Contact us to discuss Phase 4 and longer-term planning. Phase 5 details are expected, not confirmed; always check current GOV.UK and Environment Agency guidance.
Frequently asked questions
- When is ESOS Phase 5?
- No dates have been confirmed. Based on the four-year cycle, Phase 5 would be expected to have a qualification date of 31 December 2030 and a compliance date of 5 December 2031.
- Have the Phase 5 rules been published?
- No. Any Phase 5 changes would need new guidance or regulations. This article describes likely directions based on past reforms and consultations.
- Will ESOS Phase 5 make energy-saving measures mandatory?
- That is not confirmed. Government has previously consulted on a more action-focused scheme, so it is a possibility rather than a certainty.
- What should I do now to prepare?
- Complete Phase 4 thoroughly, publish a realistic action plan, improve metering and keep a single evidence base that also supports SECR, MEES, TM44 and EPC requirements.
Source: GOV.UK — Comply with the Energy Savings Opportunity Scheme (ESOS)