The way your home's energy performance is measured is changing. The familiar single A–G EPC rating is being replaced by four separate metrics — Fabric Performance, Heating System, Smart Readiness, and Energy Cost — calculated using the Home Energy Model (HEM) instead of SAP/RdSAP. The new EPCs launch from October 2026, running alongside the current system until October 2029. Your existing EPC remains valid for 10 years.
What Is Changing?
From One Rating to Four Metrics
The current EPC gives you a single A–G rating based primarily on energy cost. This hides important detail — for example, a home with excellent insulation but an old gas boiler might get the same overall rating as a home with poor insulation and a slightly newer boiler. The new system separates these into four distinct metrics:
| New Metric | What It Shows | Current EPC Equivalent |
|---|---|---|
| Fabric Performance (A–G) | Building envelope quality — walls, roof, floor, windows | Hidden within the overall rating |
| Heating System (A–G) | Heating efficiency and carbon intensity | Partially reflected in overall rating |
| Smart Readiness (A–G) | Smart controls, battery storage, grid interaction | Not measured at all |
| Energy Cost (£/year) | Estimated annual energy running costs | Roughly equivalent to the current rating basis |
For a full explanation of each metric, see our New EPC Metrics Explained page.
More Accurate Assessment
The current EPC calculation (RdSAP) uses monthly averages and struggles to model modern technologies accurately. The new HEM-based calculation uses half-hourly simulation, which means:
- Heat pumps are properly credited — their efficiency varies with outdoor temperature, which HEM captures at every timestep
- Solar PV is modelled more accurately — HEM tracks how much electricity you use on-site versus exporting to the grid
- Battery storage is modelled for the first time — current EPCs cannot account for batteries at all
- Smart controls get a dedicated metric — currently ignored in EPC assessments
Impact on Property Values
The new EPC system will gradually influence how the market perceives different properties:
Properties with Gas or Oil Heating
Fossil fuel heating (gas, oil, LPG) cannot achieve a C rating on the Heating System metric. Over time, as the new EPC format becomes familiar to buyers and estate agents, properties with low Heating System ratings may face downward pressure on valuations. This is a gradual market shift, not an overnight change.
Properties with Good Insulation
If you have invested in insulation, the separate Fabric Performance metric will make this visible for the first time. Under the current system, good fabric can be masked by a poor heating rating (and vice versa). The new system separates these, potentially improving the perceived value of well-insulated homes.
Properties with Smart Technology
Homes with solar PV, battery storage, smart heating controls, and EV charging will score well on the Smart Readiness metric. This is entirely new — current EPCs give little or no credit for these technologies. As the market increasingly values energy flexibility and self-sufficiency, this metric could become a selling point.
What Should You Do?
If You Are Not Selling or Letting
Nothing. Your existing EPC remains valid. The changes only affect you when you next need an EPC. In the meantime, any energy improvements you make will be better recognised when you do eventually get a new assessment.
If You Are Selling or Letting Soon
- If your current EPC is still valid (less than 10 years old), you can continue to use it
- If you need a new EPC after October 2026, it will be in the new four-metric format
- During the transition (October 2026 to October 2029), new EPCs will show both the old A–G rating and the new four metrics
If You Are Planning Energy Improvements
The new system changes which improvements have the most impact on your EPC. Here are the most effective upgrades under the four-metric framework:
| Improvement | Metric Improved | Typical Impact |
|---|---|---|
| Wall / loft / floor insulation | Fabric Performance | Could improve rating by 1–3 bands |
| Heat pump installation | Heating System | From D/E (gas boiler) to A/B |
| Solar PV | Energy Cost + Smart Readiness | Significant reduction in estimated annual costs |
| Battery storage | Smart Readiness + Energy Cost | Improves both (not modelled at all in current EPCs) |
| Smart heating controls | Smart Readiness | Contributes to Smart Readiness rating |
| Double to triple glazing | Fabric Performance | Moderate improvement to fabric rating |
When Does This Happen?
| Date | What Happens |
|---|---|
| Now – March 2026 | HEM: EPC consultation open (closes 18 March 2026) |
| October 2026 (target) | New HEM-based EPCs launch alongside existing system |
| October 2026 – October 2029 | Both old and new format EPCs in circulation |
| October 2029 (target) | Existing EER discontinued — all EPCs use new four-metric format |
These dates are targets — the government has acknowledged that the October 2026 launch is “ambitious”. See our Timeline & Status page for live updates.
Frequently Asked Questions
When do I need to get a new-format EPC?
Only when selling, letting, or when your current EPC expires (10 years from issue). You do not need to get one just because the system is changing. From October 2026, new EPCs will show both the old A–G rating and the new four metrics during a transition period lasting until October 2029.
Could my EPC rating go down under the new system?
The new system uses four separate metrics, so there is no direct comparison to the old single rating. Some aspects may score better (insulation is more accurately recognised), while others may score worse (fossil fuel heating scores poorly on the Heating System metric). Overall, HEM gives a more honest reflection of your home's actual performance.
Should I improve my home before selling to get a better EPC?
It depends on your property. Under the new system, the most impactful improvements are: insulation (improves Fabric Performance), heat pump (improves Heating System from D/E to A/B), smart controls and battery storage (improves Smart Readiness), and solar PV (reduces Energy Cost). The separate metrics let you target the specific area where your property scores poorly.
How will MEES work with the new EPC metrics?
The government has not yet confirmed how MEES will apply under the new four-metric framework. Currently, rental properties need at least an E. Under the new system, minimum standards could apply to individual metrics. Properties with gas boilers cannot achieve C on the Heating System metric, which could be significant if MEES applies to it. Landlords should monitor the government's position.
Will a new-format EPC cost more?
Pricing has not been confirmed. HEM assessments require more detailed data collection and longer calculation time, which may affect assessment costs. However, the centralised ECaaS platform removes software licensing costs that assessors currently pay. It is too early to say whether the overall cost will change.
Related Pages
HEM & FHS for Homeowners
Overview of what HEM and the Future Homes Standard mean for homeowners.
New EPC Metrics Explained
Full breakdown of all four new EPC headline metrics.
EPCs & HEM
Complete guide to how EPCs are changing under HEM.
HEM and Your Home
Plain English guide to what HEM means for your home and bills.