The UK government is introducing the most significant reform to Energy Performance Certificates since their creation. The new system — based on the Home Energy Model (HEM) — will launch in the second half of 2027 and fundamentally change how properties are assessed and rated.
⚠️ Updated Timeline: The government announced on 10 March 2026 that the launch of reformed domestic EPCs has been moved to the second half of 2027 (previously late 2026).
What Is Changing?
The current EPC methodology (SAP and RdSAP) is being replaced by a new assessment model. The key changes are:
- New methodology: The Home Energy Model replaces SAP/RdSAP as the underlying calculation engine
- Four new metrics replace the single A–G Energy Efficiency Rating for new certificates
- Dual-metric compliance for landlords: a primary fabric performance standard plus a secondary standard for either smart readiness or heating system
- More granular assessment: HEM captures more detail about how a building actually performs, including orientation, local climate data, and occupancy patterns
The Four New Metrics
New certificates issued after the HEM launch will display four headline metrics instead of the single A–G band:
1. Fabric Performance
Measures how well the building envelope retains heat. This covers U-values (how quickly heat passes through walls, roof, floor, and windows), thermal bridging (heat loss at junctions), and airtightness. Properties with solid walls, single glazing, or poor insulation will score poorly here.
2. Heating System
Rates the efficiency of the installed heating system. Heat pumps and modern condensing boilers score well. Older, inefficient boilers and electric storage heaters score poorly. This metric also considers how the system distributes heat around the building.
3. Smart Readiness
Assesses the property's ability to adopt and benefit from smart technology. This includes whether the property has a smart meter, smart heating controls, electric vehicle charging readiness, and the potential for demand-side response (adjusting energy use based on grid conditions). This is a forward-looking metric designed to support the transition to a smarter energy grid.
4. Energy Cost
Provides an estimated annual running cost for energy. Unlike the current EPC — which shows costs based on standardised occupancy — the new model aims to give a more realistic estimate based on the building's actual characteristics.
What Happens to Existing EPCs?
Existing EPCs remain valid for their full 10-year term. If your EPC was issued in 2020, it is valid until 2030 regardless of the system change. You do not need to get a new certificate just because the format changes.
Only certificates issued after the HEM launch date will use the new four-metric format. During the transition period, both formats will exist in the market.
Key Dates and Timeline
| Date | Event | Status |
|---|---|---|
| H2 2027 | Home Energy Model launches — new certificates use four metrics | Confirmed |
| H2 2027 – Sept 2029 | Transition period: HEM runs in parallel with current EER system | Confirmed |
| 30 Sept 2029 | Last date for issuing EER-based EPCs | Confirmed |
| 1 Oct 2029 | All new EPC assessments must use HEM methodology only | Confirmed |
| 1 Oct 2030 | All privately rented properties must meet EPC C (or equivalent under HEM) | Confirmed |
See the full timeline: EPC reform timeline
What This Means for Landlords
The reform introduces dual-metric compliance. Landlords will need to meet a primary fabric performance standard and a secondary standard for either smart readiness or heating system. The exact thresholds are still being finalised following the Jan–Mar 2026 consultation.
The practical implication: properties with good insulation (fabric performance) but old heating systems may still comply if they meet the smart readiness threshold. Conversely, a property with a brand-new heat pump but poor insulation may fail on fabric performance.
The £10,000 cost cap applies regardless of which metric pathway a landlord follows. Spending from 1 October 2025 counts towards the cap.
Read the full landlord guide: Landlord EPC rules 2030
What This Means for Homeowners Selling
The requirement to have a valid EPC when marketing a property for sale does not change. There is no minimum rating required to sell — you simply must have a valid certificate. If your existing EPC is still within its 10-year validity, you can use it even if it was issued under the old system.
Read more: EPC rules for sellers
What This Means for Homeowners Generally
The new metrics will give homeowners a much better understanding of their property's energy performance. Instead of a single letter grade, you will see how your insulation, heating, and smart readiness each contribute to overall efficiency. This makes it easier to identify the most impactful improvements.
For homeowners considering improvements now: any upgrades you make will still be reflected in the new system. Better insulation, a more efficient heating system, or solar panels will improve your metrics regardless of which model is used to assess them.
See improvement options: How to improve your EPC rating
Official Government Sources
For the latest updates on the Home Energy Model reforms, see the official GOV.UK HEM consultation page and the government's Warm Homes Plan.
About This Guide
This guide was researched and written by the EPC Certificate UK Editorial Team, specialists in UK energy performance regulations. All information is sourced from official government publications, regulatory announcements, and industry best practice guides.