EPC ratings explained: A to G

An Energy Performance Certificate, or EPC, is a legal document that records how energy-efficient a property is. It rates the building on a scale from A to G — A being the most efficient, G the least — and includes an estimate of typical annual running costs, a measure of carbon dioxide emissions, and a list of improvements the assessor believes would raise the rating.

EPCs were introduced in England and Wales in 2007 under the Energy Performance of Buildings Directive. They became mandatory for almost every property transaction shortly afterward. Today, an EPC is required by law whenever a residential property is built, sold, or rented — and the certificate must be available to prospective buyers or tenants from the point of marketing. Scotland and Northern Ireland operate equivalent schemes with their own administrative arrangements but similar A-to-G banding.

EPCs are produced by accredited domestic energy assessors. The assessor visits the property, measures floor area, records the construction type, surveys the heating system and controls, notes the type and amount of insulation in walls and roof, identifies the glazing, and records any low and zero carbon technologies present — solar PV, solar thermal, heat pumps, biomass, mechanical ventilation with heat recovery. From those inputs, the assessor produces a SAP score from 1 to 100, which maps to a band.

A certificate is valid for 10 years from the date of issue. During that period it can be used as many times as needed for sales or lettings, and remains the legal record even after improvements unless a new assessment is commissioned. Around 27 million EPCs sit on the live register at any time, covering most of the English and Welsh housing stock.

The certificate has commercial weight beyond compliance. Mortgage lenders increasingly factor the EPC into lending decisions, particularly for buy-to-let and energy-efficient mortgage products. Conveyancers will surface the EPC during a sale. Local authorities use the data for housing strategy. And — the reason most homeowners care — many of the largest UK home energy grants use the EPC band as either a qualification gate or a priority signal.

Every EPC band sits on top of a numerical score. The score runs from 1 to 100 (and can exceed 100 for properties that export more energy than they import). This is the SAP score — Standard Assessment Procedure — the government's official methodology for measuring the energy performance of dwellings.

New-build homes are assessed under full SAP, using the actual design data: U-values, air permeability test results, specified glazing, declared heating system efficiency, ventilation strategy. Because the inputs are precise, the resulting score is precise. New builds therefore tend to band high, often B or A, when the construction matches the design.

Existing dwellings are assessed under RdSAP, the Reduced Data variant. The assessor does not have access to design data, so the methodology fills the gaps with sensible defaults based on the assessor's on-site observations and the age of the building. RdSAP assumes typical U-values for construction types of a given era, applies standard occupancy assumptions, and uses fixed fuel-cost figures published annually by the Building Research Establishment.

The SAP score-to-band thresholds are fixed across both methodologies:

Minimum Energy Efficiency Standards set a legal floor for the EPC band of privately rented properties in England and Wales. They were introduced under the Energy Efficiency (Private Rented Property) Regulations 2015 and have phased in over the years since.

Current rules: Since 1 April 2018, private landlords cannot grant a new tenancy on a property with an EPC band below E. Since 1 April 2020, the same rule applies to all existing tenancies. A landlord whose property is rated F or G must either improve it to band E (or above), register a valid exemption, or stop letting it.

The exemptions: The most commonly used exemptions are the £3,500 cost-cap (the landlord has spent up to £3,500 attempting to reach band E but the rating remains below), the consent exemption (the tenant or a third party with consent rights has refused the works), and the property devaluation exemption (an independent surveyor certifies that the proposed works would reduce property value by more than 5%). Exemptions are registered through the PRS Exemptions Register on gov.uk and last 5 years.

What is proposed: The previous government consulted on raising the MEES floor to band C for new tenancies (originally targeted at 2025) and for all tenancies (originally targeted at 2028). Both deadlines have been pushed back and the exact form and timing of any future tightening remains under DESNZ review. Landlords should treat band C as a likely future floor rather than a fixed current obligation, and watch for primary legislation rather than relying on press releases.

What it means for owner-occupiers: MEES does not apply to owner-occupied homes. But the same upward trajectory affects mortgage availability — several lenders now offer preferential rates on properties at C or above, and a few have signalled intent to lend less, or at higher rates, against very inefficient stock. Property value at sale is increasingly influenced by EPC band, particularly in markets with engaged eco-conscious buyers.

Several pieces of UK research — notably MHCLG analyses and work from the property data firms — have found a measurable price premium for higher-rated properties, particularly the step from D to C. The premium varies by region and market segment, but typically falls in the 4-14% range when comparing otherwise-equivalent properties. The differential widens during energy price spikes (buyers price in running cost) and narrows during cheap-energy periods.

For sellers, an updated EPC after improvements is often worth commissioning even if the existing one is still valid. The current rating on the marketing material affects portal filters and buyer perception. For buyers, the EPC's recommended improvements list — and the indicative annual cost figures — are a useful negotiating reference, particularly for properties below band C.

See our companion guide on EPC and property value for the underlying research and a more detailed look at how the band interacts with sale price and mortgage availability.

The A-to-G banding is consistent UK-wide, but the grant landscape, register administration, and assessment methodology differ between the four nations.

Scotland operates a parallel scheme with EESH (Energy Efficiency Standard for Social Housing) for the social rented sector and Warmer Homes Scotland for owner-occupiers and private tenants. The EPC register is the Scottish EPC Register, separate from the MHCLG database. Scottish Council Tax bands extend to E for some GBIS-equivalent routes. Full detail in our Scotland regional guide.

Wales runs the Nest scheme through Welsh Government, covering 22 local authorities with a combined offer of advice, energy efficiency assessment, and funded improvements for eligible households. The MHCLG register covers Welsh properties for compliance purposes. Full detail in our Wales regional guide.

Northern Ireland uses the EPC NI methodology administered by the Department of Finance. The NI Sustainable Energy Programme funds energy improvements for low-income households. The Boiler Upgrade Scheme does not extend to Northern Ireland — separate heat pump grant routes apply through NISEP.