The government's partial response to the Energy Performance of Buildings consultation, published 21 January 2026, confirms the shape of the reformed domestic certificate. The launch has since moved to the second half of 2027, but what it will show is settled.

The four headline metrics

  • Fabric performance — how well the building itself retains heat, independent of what heats it. Walls, roof, floor, glazing, airtightness.
  • Heating system — the efficiency and type of the system installed.
  • Energy cost — closest to what the current rating does, and the one occupants care about most directly.
  • Smart readiness — the capacity to shift and control energy use: controls, storage, time-of-use capability.

Secondary metrics will include energy demand and a carbon-based measure. Ten-year validity is retained.

Why separating them is an improvement

The current single letter conflates things that behave very differently. A solid-walled Victorian house with a brand-new boiler and a well-insulated 1990s house with an ageing one can land on the same band, while needing completely opposite work.

Splitting fabric from heating fixes that. It also makes the certificate much more useful for planning retrofit, because fabric-first sequencing becomes visible on the document itself rather than something an assessor has to explain.

The uncomfortable side

It will be harder to flatter a property. Under a single cost-weighted metric, swapping a heating system can lift a band while the building remains a sieve. Under four metrics, the fabric score sits there regardless, in its own box.

For London's solid-walled stock that is a genuine consideration. Many properties that currently reach a respectable band on the strength of an efficient boiler will show a weak fabric score alongside it. That is accurate. It is not flattering.

How this connects to the rented sector

The private rented sector standard from 1 October 2030 requires a C-equivalent rating plus a secondary standard — either heating system performance or smart readiness, at the landlord's choice. Those map directly onto two of the four metrics, which is not a coincidence.

Certificates lodged today remain valid for their full ten years under the current method. If you need one, book online for £69 — or use the free EPC review to see where you stand first.