ESOS Phase 4 runs from 6th December 2023 to 5th December 2027. The qualification date is 31st December 2026, and qualifying organisations must complete their ESOS assessment and submit their notification of compliance by 5th December 2027.
The qualification date determines whether an organisation falls within ESOS Phase 4. It is different from the reference period used to calculate total energy consumption. The reference period must cover 12 consecutive months, including 31st December 2026 and end before the compliance deadline.
There is also a Phase 3 deadline during the Phase 4 compliance period. Organisations that qualified for Phase 3 must submit their second and final annual Progress Update by 5th December 2026.
