An Energy Performance Certificate (EPC) contains information about how energy is used in a home or a business premises, along with details of how much the energy used costs.

How does an EPC work?

The EPC rates the property’s performance in terms of energy use per square metre of floor area, energy efficiency based on fuel costs, and environmental impact based on carbon dioxide (CO2) emissions. This provides an energy efficiency rating and an environmental impact (CO2) rating.

There are seven bands for both ratings, from A to G. The energy efficiency rating is colour-coded from green to red, with the green end of the scale indicating that the property is very energy efficient, with lower running costs, and the red end of the scale indicating it is not energy efficient and has higher running costs.

There is also a numerical rating from 1 – 100. The bigger the number the more energy efficient the property is and the lower the fuel bills will be.

The environmental impact rating is colour-coded from blue to grey, signifying ‘very environmentally friendly – lower CO2 emissions’ at the blue end of the scale through to ‘not environmentally friendly – higher CO2 emissions’ at the grey end. Again, there is a numerical rating, from 1 – 100, and the bigger the number, the less impact the house has on the environment.

Estimated Fuel Costs

The EPC assessor uses standardised assumptions about the property’s occupancy, heating patterns and geographical location to construct a table that indicates how much it will cost to provide lighting, heating and hot water to this dwelling.

The table sets out the current energy use alongside the potential use if a range of recommendations are followed. The same is done for carbon dioxide emissions.

Costs are listed for lighting, heating and hot water – again, there is a figure for the current and potential cost, showing how much could be saved in cash terms.

If you are scrutinising an EPC, always check the date the certificate was issued, because fuel prices can increase over time.

Detailed Performance Summary

Having provided details of actual and potential energy use and cost outlay, the EPC provides a summary of the property’s energy performance-related features. These include walls, roof, floor, windows, main heating, heating controls, secondary heating (if applicable), hot water and lighting.

Each element is assessed against the following scale: Very poor/Poor/Average/Good/Very good. So, for example, your wall might be described as: Cavity wall, as built (no insulation). It would then probably be described as ‘poor’ for its performance in terms of both energy efficiency and environmental impact. A pitched roof with 250mm loft insulation, however, might warrant being described as ‘good’. If there was low energy lighting in 75% of fixed outlets, this would rank as ‘very good’ by both measures.

After taking all the individual ratings into account, the assessor would decide the property’s overall energy efficiency and environmental impact ratings as shown in the colour-coded charts. For a full example of an energy performance certificate, visit the DirectGov website or click here.

EPC recommendations

The EPC provides a list of suggested measures to achieve cost effective improvements to performance ratings. The table outlines the typical savings per year and the potential performance ratings after the improvements have been made. The improvements are divided into ‘lower cost measures’ of up to £500 and ‘higher cost measures’ for larger amounts.

So, for example, low cost measures such as fitting cavity wall insulation might achieve a typical annual saving of over £400, while installing low energy lighting in all fixed outlets would deliver a saving of over £11.

High cost measures might include fitting a hot water cylinder thermostat or replacing an old boiler with a more efficient model. Further suggestions – for example, fitting double glazing and solar heating panels – are included for those aiming for the highest possible standards for their property. Explanatory text is provided on each measure to help the reader decide what is involved in taking the suggested action. This includes information on which improvements may be eligible for funding through the government’s Green Deal (see below).

There is no requirement to act on the recommendations in the report. However, doing so could make the property more attractive for sale or rent by making it more energy efficient.

EPC-holders can go online to the EPC Adviser (, enter their reference number off the certificate and see how much could be saved in terms of money and CO2 emissions.

When you are required to get an EPC

An EPC is required by law when a building is built, sold or put up for rent. If you are a landlord or homeowner and need to provide an EPC, you’ll need to contact an accredited domestic energy assessor. They will carry out the assessment and produce the certificate.

Domestic energy assessors may be employed by a company (like an estate agent or energy company) or be self-employed. You should always check that your domestic energy assessor belongs to an accreditation scheme.

EPCs are valid for 10 years and the fee charged by the assessor will be at the market rate. The size and location of your property will be determining factors.

When you’ll be given an EPC

By law you should receive an EPC in the following cases:

When you are considering buying a property, you should be provided with an EPC, free of charge. This applies to new properties and existing stock.

If you are considering renting a property, you should get an EPC from the landlord, free of charge. That said, you don’t need an EPC when you are thinking of just renting a room with shared facilities rather than renting the whole property.

In all cases the intention is to allow you to compare the energy efficiency and costs associated with the property.

You can apply for and receive an EPC from an energy assessor simply because you want to know how energy efficient your property is, and make improvements suggested by the report.