At a glance
An Energy Performance Certificate (EPC) is a standardised assessment of how energy efficient a property is. It rates the home on a scale from A to G – A being the most efficient and G the least – and provides an estimated annual energy cost, a breakdown of the main factors affecting the rating, and a list of recommended improvements with their likely impact on the score. Every EPC is produced by an accredited domestic energy assessor who inspects the property and enters its characteristics into a government-approved software model that calculates the rating.
The EPC has become increasingly important beyond its original purpose as a disclosure document for property sales. For landlords, minimum EPC requirements now affect which properties can legally be let. For buyers and sellers, the rating increasingly influences property values and mortgage lending decisions. For homeowners considering improvements, the EPC report provides a prioritised list of the measures most likely to move the rating – which is exactly the starting point any energy improvement programme should use.
What an EPC is and what it measures
The EPC score runs from 1 to 100, with higher scores representing better energy efficiency. The A to G bands divide this scale into seven segments. The score is calculated using the Standard Assessment Procedure (SAP), which is the government’s methodology for rating the energy performance of homes. SAP assesses the fabric of the building – walls, roof, floor, windows and doors – the heating system and its controls, hot water provision, ventilation, and any renewable energy features such as solar panels.
Crucially, the EPC measures the energy efficiency of the building and its fixed services, not the behaviour of the occupants. A household that heats the home to 25°C and leaves windows open in winter will have higher energy bills than the EPC predicts – but the certificate itself does not change. This is why the estimated running costs shown on an EPC are a modelled figure rather than an actual bill prediction, and why two identical homes with different occupants will have the same EPC score but different energy bills.
The A to G rating bands explained
The most significant practical boundary in the current EPC system is the E/F divide – properties rated F or G cannot legally be let to new tenants without a registered exemption. The government has signalled an intention to raise the minimum lettable standard to C by 2030 for new tenancies, which would affect a large proportion of the private rented sector. Homeowners looking to sell are also finding that mortgage lenders are increasingly incorporating EPC ratings into their risk assessments, and that a D or E rated property can affect both the buyer’s mortgage offer and the sale price achieved.
When you legally need an EPC
An EPC is legally required whenever a property in England, Wales or Scotland is sold, newly built, or let to a new tenant. The certificate must be commissioned before the property is marketed for sale or rent – it is not something that can be obtained after an offer has been accepted. Estate agents and lettings agents are required to include the EPC rating in any advertisement for the property, and a copy of the full certificate must be made available to any prospective buyer or tenant on request.
An EPC is valid for 10 years from the date of issue. If a property has been sold or let multiple times within the 10-year validity period, the same certificate remains valid as long as no significant changes to the building fabric have been made. If energy improvement work has been carried out – new insulation, a new boiler, double glazing or solar panels, for example – commissioning a new EPC is worthwhile, as the improvements will likely move the rating up and the updated certificate reflects the current performance of the property accurately. You can check whether your property already has a valid EPC by searching the national EPC register on the government’s website.
How to improve your EPC rating
Every EPC report includes a section of recommended improvements ranked by the number of rating points each is estimated to add. These recommendations are specific to the property assessed and are the most reliable guide to which measures will have the greatest impact on that particular home. However, some improvements consistently appear across the majority of UK homes and are worth understanding in general terms.
For most homes rated D or E, loft insulation is the highest-impact, lowest-cost improvement available and should almost always be the starting point. Cavity wall insulation, where the construction type allows it, is the other high-value measure at a similar price point. A smart thermostat with full heating controls adds fewer points to the SAP calculation but has a meaningful real-world impact on running costs beyond what the EPC captures. For homes with solid walls rather than cavity construction, draught proofing and heating controls are the most accessible improvements before the larger investment of solid wall insulation is considered.
EPC rules for landlords
Since April 2020, landlords in England and Wales have been legally required to ensure that any property let to a new or renewing tenant achieves a minimum EPC rating of E. Properties rated F or G cannot be let without a registered exemption – which covers situations where improvements are not technically feasible, where the cost of improvements exceeds the maximum allowable spend, or where the landlord has a listed building or other protected property status. Exemptions must be registered on the government’s PRS Exemptions Register and are valid for five years.
The government has signalled that the minimum standard for new tenancies will rise to C by 2030, with existing tenancies following by 2033. If confirmed, this will require significant improvement works on a large proportion of the private rented stock – the majority of F and G rated properties are older solid-wall construction where achieving a C rating involves substantial investment in insulation, heating and glazing. Landlords with properties currently rated D or E should be considering the planned works required to reach C as part of their medium-term property investment planning.
Check the EPC register before commissioning a new assessment. EPC certificates are valid for 10 years and are registered on the national EPC database. Before paying for a new assessment, search the register to see whether your property already has a valid certificate – many properties do, particularly if they have been sold or let recently. The register is free to search and certificates can be downloaded at no charge.
Common mistakes and misconceptions
Share on socials:
