EPC Reform 2026: What the New Four-Metric Rating System Means for Landlords

The EPC as you know it is being replaced. The government’s Warm Homes Plan, published in January 2026, confirmed that the single A–G energy efficiency rating will be replaced by a four-metric system that separately measures fabric performance, heating efficiency, smart readiness and energy cost. This is the most significant change to the Energy Performance Certificate since its introduction in 2007 — and it has direct consequences for how landlords plan improvements ahead of the October 2030 compliance deadline.

This guide explains what each of the four new metrics measures, why the government is making this change, how it affects the 2030 deadline, and what landlords should be doing right now to prepare.

What’s changing

The current EPC uses a single metric: the Energy Efficiency Rating (EER). This is a score from 1 to 100 (displayed as bands A to G) based on the estimated annual energy cost per square metre of floor area. It is a crude measure. Two properties with completely different characteristics can score the same EER if their estimated running costs happen to be similar.

The new system replaces this single score with four separate metrics, each rated independently. The aim is to give a more accurate, more useful picture of a building’s energy performance — one that separates “how well is this building built?” from “how cheap is the fuel it uses?”.

The four new metrics

1. Fabric Performance

This metric measures how well the building envelope — walls, roof, floors and windows — retains heat. It is independent of the heating system. A well-insulated property with double-glazed windows, filled cavity walls and adequate loft insulation will score highly regardless of whether it is heated by a gas boiler or a heat pump.

Fabric Performance captures the elements that are hardest (and most expensive) to retrofit: wall construction, window quality, draught levels and thermal bridging. It rewards landlords who invest in insulation and glazing — improvements that reduce energy demand permanently, no matter what heating technology the property uses in the future.

2. Heating System

This metric assesses the efficiency and carbon intensity of the heating and hot water system. Properties with heat pumps, modern condensing boilers with full controls, or district heating connections will score well. Properties with old, inefficient boilers, electric storage heaters or direct electric heating will score poorly.

Critically, this metric separates heating from fabric. Under the current single-metric system, a new condensing boiler can mask poor insulation because cheap gas keeps estimated costs low. Under the new system, a well-rated heating system cannot compensate for poor fabric — both must meet the standard independently.

3. Smart Readiness

This is the most novel metric and the one that has generated the most discussion. Smart Readiness measures the property’s capacity for:

• Smart heating controls: Programmable thermostats, room-by-room zoning, internet-connected heating management
• Demand flexibility: Ability to shift energy consumption to off-peak periods, integration with time-of-use tariffs
• Grid interaction: Readiness for solar PV, battery storage, electric vehicle charging and smart meters
• Monitoring: Energy monitoring systems that help occupants understand and reduce their consumption

Smart Readiness is forward-looking. It assesses not just what the property has today, but how well it can adapt to the electrified, flexible energy system that the grid is moving towards. For landlords, the practical implication is that smart thermostats, TRVs and smart meters will contribute to compliance in a way they currently do not under the simple cost-based EER.

4. Energy Cost

This metric is the closest to the current EER. It estimates the annual energy cost for a standardised occupant based on the property’s characteristics, fuel type and tariff assumptions. It provides the consumer-facing “how much will this cost to heat?” information that tenants care about most.

The difference from the current EER is that Energy Cost is one of four metrics, not the only one. A property cannot achieve compliance by scoring well on Energy Cost alone if it fails on Fabric Performance or Heating System.

Why the government is changing it

The fundamental problem with the current EPC is that it rewards cheap gas over genuine energy efficiency. Consider two properties:

• Property A: A poorly insulated Victorian terrace with a new condensing gas boiler. The gas is cheap, so the estimated annual cost per square metre is moderate. It scores Band D (SAP 62).
• Property B: A well-insulated 1960s semi with full cavity wall insulation, loft insulation and double glazing, but with an older (non-condensing) gas boiler. Its fabric is excellent but the boiler drags down its estimated costs. It also scores Band D (SAP 62).

Under the current system, these properties look identical. Under the four-metric system, Property B would score much higher on Fabric Performance (good insulation) while Property A would score poorly (leaky building). The new system tells tenants and landlords where the real problems lie — and where investment will make the biggest difference.

This matters because the UK’s path to net zero requires electrifying heating (replacing gas boilers with heat pumps). A heat pump in a well-insulated building works efficiently and cheaply. A heat pump in a poorly insulated building runs constantly, costs more than gas to run, and fails to deliver comfort. The four-metric system is designed to drive fabric-first investment — insulate properly, then electrify.

The 2030 compliance requirement under the new system

Under the reformed EPC system, the October 2030 Band C requirement translates to a multi-metric threshold. The current proposal is that a property must meet Band C on Fabric Performance plus either Heating System or Smart Readiness.

This means insulation is no longer optional. Under the current system, you could theoretically reach Band C with a new boiler alone, without touching the building fabric. Under the new system, Fabric Performance is a mandatory component of compliance. Cavity wall insulation, loft insulation, glazing and draught proofing become essential, not optional extras.

Timeline: HEM, SAP and the transition

The four-metric EPC is powered by the Home Energy Model (HEM), a new calculation engine that replaces the Standard Assessment Procedure (SAP). The transition timeline:

• Late 2026: HEM launches for new-build assessments. The new four-metric format begins appearing on EPCs for new properties.
• 2027–2029: Transitional period. Both SAP and HEM assessments are valid for existing dwellings. Landlords can choose to get a SAP-based or HEM-based assessment.
• 1 October 2029: SAP is discontinued. All new EPC assessments from this date use HEM and produce the four-metric format.
• 1 October 2030: Compliance deadline. Properties must hold a valid certificate showing Band C compliance — whether that certificate was produced under SAP (before October 2029) or HEM (after).

For the full technical analysis of HEM, see our HEM methodology guide for landlords.

The safe harbour: get rated under SAP before October 2029

There is a clear strategic advantage to completing improvements and getting a new EPC under the current SAP methodology before October 2029:

• SAP is a known quantity. You can predict your score with reasonable confidence based on the improvements you make.
• A SAP-based Band C certificate issued before October 2029 remains valid for 10 years, covering you well past the 2030 deadline.
• HEM may score some properties differently. Properties that currently hit Band C under SAP might fall short under HEM, particularly those that rely on gas heating efficiency rather than fabric quality.
• There is no requirement to get a HEM-based assessment if you already hold a valid SAP-based certificate.

What this means for property improvements

The four-metric system officially endorses what energy efficiency experts have advocated for years: a fabric-first approach. For landlords planning improvements, this means:

• Insulation is now the priority: Cavity wall insulation, loft insulation, floor insulation and glazing directly improve Fabric Performance, which is the mandatory metric for compliance.
• Heating upgrades are still valuable: A heat pump or modern condensing boiler improves the Heating System metric. Combined with good fabric, this gives the strongest overall result.
• Smart controls matter more: Smart thermostats, TRVs and smart meters contribute to Smart Readiness, giving landlords an additional route to compliance alongside Fabric Performance.
• Gas boiler replacements alone are riskier: Under the current system, a new gas boiler in a leaky building can push a property to Band C. Under the four-metric system, it will not — the fabric must also meet the standard.

What landlords should do right now

The four-metric system is coming, but the transition provides time to act. Here is the practical advice:

• Step 1: Check your property’s current EPC. Know your SAP score, your band and your recommended improvements.
• Step 2: Prioritise fabric improvements. If your EPC recommends loft insulation, cavity wall insulation or glazing upgrades, do these first. They will help under both the current SAP system and the future four-metric system.
• Step 3: Consider the heating system second. If the property has a gas boiler and you are considering a heat pump, the £7,500 BUS grant makes this financially attractive.
• Step 4: Add smart controls. Smart thermostats and TRVs are cheap (£200–£500) and will contribute to the Smart Readiness metric under the new system.
• Step 5: Get reassessed under SAP before October 2029. Lock in your Band C certificate while the methodology is predictable.

For a full breakdown of improvement costs and SAP point gains, see how to improve your rental property’s EPC rating. For the specific requirements of the October 2030 deadline, see EPC Band C requirements for landlords.