Energy performance certificates (EPC) explained
The current EPC metric
An energy performance certificate (EPC) shows how energy efficient a building (domestic and non-domestic) is. The current metric for EPCs rates a home from A (very efficient) to G (least efficient). An EPC includes:
- energy rating and Standard Assessment Procedure (SAP) score
- breakdown of the property’s energy performance (features of the property and primary energy use)
- how the features affect the energy bills
- impact on the environment (carbon emissions)
- steps to take to save energy and improve the property’s energy efficiency
- the energy assessor who carried out the assessment.
Once the certificate has been issued, it is valid for 10 years.
An EPC contains valuable information that ca help you understand your homes energy performance. It helps you identify what is needed to reduce your fuel bills and reduce your property’s carbon emissions.
If you decide to sell or rent out your home or make major renovations, you will need a valid EPC (not expired). You will need an approved domestic energy assessor (DEA) to produce the EPC. You can find a local assessor by visiting GOV.UK - Get a new energy certificate
Currently, rental properties need an EPC of E rating or above to be able to be let out (unless there is a valid exemption). In October 2030, this will change to a C rating or above. An EPC will guide you with what improvements you need to make to reach a higher rating. If you are a landlord and need advice on the change in EPC rating for rental properties, please complete the landlord assistance survey if you’d like to be contacted: Landlord Retrofit HUB online sign-up form. Or you can email environment@westsuffolk.gov.uk.
The cost of having an assessor visit your property to carry out the relevant assessment to provide you with your property’s EPC varies. According to Check a Trade - Energy Performance Certificate Cost in the UK 2026, it can cost between £65 to £120. The size of the property, type of house, where you live, number of bedrooms and the EPC assessor determines the cost.
The new EPC metric: the four-metric framework
The government have announced, in the Energy performance of buildings (EPB) consultation (January 2026), that the current single A-G EPC rating is being replaced by four separate metrics:
- fabric performance
- heating system
- smart readiness, and
- energy cost.
Three of the metrics will be rated A-G, energy cost will be shown as an estimated annual figure (in £).
Fabric performance
Fabric performance includes measures such as loft insulation, wall insulation, floor insulation, doors and windows, airtightness, thermal bridges and thermal mass. These features will affect the fabric rating as each measure affect the retention of heat. Having a separate metric from heating system will show the investment into insulating the property, whereas the current metric system overlooks the buildings fabric performance.
Heating system
This metric will rate the type of heating system the building has by assessing the efficiency and carbon intensity of both the heating and hot water system. To do this, they evaluate how much energy the system uses to produce heat and how much carbon is produced. Heating systems such as heat pumps and low-carbon heat network are proposed to have a rating of c or above, whereas gas, oil or LPG boilers will not be able to achieve a C rating.
Smart readiness
This is a new metric to be consider within EPCs, it will measure a home’s capacity to interact with smart energy systems and the wider electricity grid. Smart readiness does not only include smart metres but also EV chargers, solar PV, smart heating controls and battery storage for the solar PV system. As a gas boiler caps the heating system metric to a D rating, landlords with rental properties with gas boilers have the opportunity to achieve a high rating in smart readiness to achieve an overall higher EPC rating.
Energy cost
The energy cost figure will be provided using standardised fuel prices (based on prices when the EPC is generated) and Home Energy Model's half-hourly simulation to estimate the overall annual energy bill. If the property has solar PV and battery storage, that particular system is fully modelled meaning it will reduce the estimated cost for those homes that generate and store electricity using that system.
The new four-metric EPC framework target launch date is late 2027 with the new framework fully taking place in 2029. If you have any queries about EPCs, please email environment@westsuffolk.gov.uk.
