The short answer
The Energy Savings Opportunity Scheme (ESOS) requires large undertakings to assess their energy use and report on savings opportunities, and lighting is one of the most common opportunities identified. Phase 4 qualification is based on 31 December 2026, with notification due by 5 December 2027.
Who is in scope
Broadly, a large undertaking has 250 or more employees, or both turnover over £44 million and a balance sheet over £38 million, including relevant group companies. Phase 3 used a qualification date of 31 December 2022.
Key dates
| Milestone | Date |
|---|---|
| Phase 3 second action-plan progress update | 5 December 2026 |
| Phase 4 qualification date | 31 December 2026 |
| Phase 4 notification deadline | 5 December 2027 |
Where lighting fits
Lighting upgrades and controls are often quick, well-evidenced measures for ESOS action plans. Our surveys give fitting counts, hours and estimated savings that feed straight into an assessment.
Questions
Does ESOS require us to install LED?
ESOS requires assessment and reporting. Phase 3 introduced action plans and progress updates, but the scheme does not itself require you to install specific measures.
Related services
Lighting surveys and lux testing
Lux readings, condition surveys and energy audits for existing lighting.
LED lighting upgrades
Swap fluorescent, halogen and metal halide fittings for efficient LED.
Lighting controls
Presence detection, daylight dimming and DALI systems.
Lighting maintenance contracts
Planned maintenance, emergency lighting tests and reactive repairs.
Last reviewed 9 November 2026. This guide is general information, not legal, tax or engineering advice for a specific site.