ESOS Phase 4 deadline and timeline

The Phase 4 dates

ESOS runs on a fixed four-year cycle and Phase 4 follows the pattern of Phase 3 without the extension that phase needed. The dates that matter are below.

Lead assessors must be on an approved register at the time they sign off, and the director who signs must be at board level. Both of those are easy to arrange in January and hard to arrange in November.

A working-back timeline

Most Phase 3 problems came from starting too late. A comfortable Phase 4 looks like this.

If you are starting later than this, the order still holds; the compression happens in the audit phase, and it is the audit phase that costs more when rushed.

Getting the data right first

The single biggest determinant of how smooth an ESOS assessment is turns out to be data quality. An organisation with half-hourly electricity data, read gas meters and fuel-card records for its vehicles can complete the measurement stage in days. One with estimated bills, unmetered sites and a vague idea of mileage spends weeks reconstructing it and pays the assessor for the privilege.

This is where the overlap with everyday energy management is useful. Consolidating bills, fixing estimated reads and getting half-hourly data flowing are things worth doing anyway, and they make the assessment cheaper. Invoice validation and a business energy audit produce exactly the dataset ESOS needs.

Frequently asked questions