Energy Performance Certificate: In-Depth Guide


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What Is an Energy Performance Certificate (EPC)?

The Energy Performance Certificate (EPC) rates the energy efficiency of a domestic dwelling. Following assessment, properties are rated on a scale. A is the highest rating, meaning the property is highly energy-efficient and G is the lowest and least energy efficient. The average EPC rating for the UK is band D.

What is an Energy Performance Certificate?

The Energy Performance Certificate (EPC) contains information about how much energy a property consumes and the average cost of the energy bills. The certificate also contains suggestions and recommendations for improving the energy efficiency of the property. Such as:

  • Low energy light bulbs
  • Double glazing with low-E glass
  • External and internal wall insulation
  • Loft and solid floor insulation
  • Solar water heating

Residential properties are rated on a scale from A to G (A being the most efficient and G the worst).

The EPC must be provided when a house is built, sold or rented.

The EPC was initially introduced in the UK as part of the Home Information Pack (HIP or Hip) in 2007. HIPs drew so much criticism for stalling housing sales they were discontinued in 2010, but the EPC continued as a requirement for sellers and for landlords of rented properties.

In 2018 (introduced in April 2020), the Government announced that rental properties had to achieve a minimum EPC rating of 'E'.

In 2021, a new Government proposal was announced that will require all new rental properties to be a minimum rating of 'C' by December 2025. All rental tenancies must be C-rated by December 2028. As yet, this is a proposal, but landlords are taking it seriously and making preparations. However, there could be more changes and amendments before the bill is passed.

EPCs are a little different in Scotland and must be displayed in the property, read more here.

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Upgrading your windows can improve your EPC rating.

When do I need an EPC?

All domestic properties in England and Wales must provide an EPC. Other buildings must provide a non-domestic EPC. Public buildings in England must display a Display Energy Certificate.

When Do I Need an EPC?

  • Yes, if you want to sell your house – the seller must produce a current certificate before the sale can complete
  • Yes, if you build a house – all new houses must have an EPC issued
  • Yes, if you’re a landlord and want to rent a property to a new tenant
  • No, if you’re buying a house – the seller is responsible for the cost
  • No, if you have a lodger in your home
  • No, if you’re a tenant renting a property – the landlord is responsible for the cost and for any required energy efficiency improvements

Buildings That Are Exempt and Don't Need an EPC:

  • Listed buildings
  • Buildings that are for temporary use of less than two years
  • Holiday accommodation that’s let for less than four months of the year
  • Residential buildings that are used for less than four months of the year
  • A stand-alone building with less than 50 square metres of floor space
  • Buildings due to be demolished
  • Workshops and agricultural buildings that don’t use much energy
  • Places of worship

If you intend to sell or rent out a property you need to get an EPC issued before you can put it on the market. All rental properties must be band E or higher (from 2025, this will increase to band C).

The energy performance certificate explained part 1

The Energy Performance Certificate (EPC) Explained…

The main benefit of the EPC is that a buyer or renter can make direct comparisons between prospective properties, so that they can understand what the running costs are.

The certificate is also useful to a homeowner so that they can see where they can make savings and improvements on their energy bills.

Click on the buttons 1-8 (left) to read more.

The energy performance certificate explained part 2

Property Information

The details of the property for the certificate, are at the top of the page. The date of assessment/certificate are included, worth noting as a certificate expires after ten years.

The reference number is the unique number for your certificate and it can be used to search on the EPC register to ensure that the certificate is authentic.

Standard Assessment Procedure (SAP) is the term used for how the government measures the energy efficiency of a building and compares buildings with each other (to inform reports and policies). The SAP assessment is based on standard (not actual) occupancy and behaviour for homes, so that properties can be compared like-for-like.

  • RdSAP is a Reduced data SAP and is used for existing properties.
  • SAP is used to assess newly built properties.
The energy performance certificate explained part 3

Estimated Energy Costs

The energy costs for lighting, heating and hot water are calculated and displayed in a table.

These costs are calculated from several factors in your property, which are outlined under the summary of the home’s energy performance related features such as: the heating system in the property; the insulation efficiency of the walls, roof, windows and floors.

A standardised occupancy and behaviour is used to make the calculation, such as how many people live in the property, how many baths or showers they have and for how many hours a day the heating is switched on. This allows properties to be compared like-for-like. The energy bill calculation only includes heating, hot water and lighting and not electricity used for any other purpose such as TV, laptops or cooking.

For example, two properties, semi-detached, with floor space of 135-144 m2, the estimated energy costs for heat, light and hot water:

  • An A rated home costs a total of £1,701 over three years – equal to just under £45 a month.
  • A G rated house costs a total of £11,010 over three years – equal to just over £300 a month.
The energy performance certificate explained part 4

Energy Efficiency Rating

The rating for the property is displayed in a similar style to the energy efficiency rating for home appliances (such as fridges). This is a colour coded visual that’s quick and easy to understand.

The certificate indicates what the score and band rating for the property is, from A to G.

A is the highest rating, meaning a property is highly energy efficient and G is the lowest and least energy efficient, with potentially high energy bills.

Rating is based both on the energy use per square metre of floor area (this is noted under the summary of energy performance on page three) and the energy efficiency measured by fuel costs.

The rating also shows the potential score you could achieve if the recommendations on the certificate are applied.

For example, two properties, semi-detached, with floor area 135-144 m2

  • A rated score of 95 with a potential to achieve a 96 (by installing solar water heating).
  • G rated score of 11 with a potential to achieve a 76 (by implementing all the recommendations).
The energy performance certificate explained part 5

Top Actions/Recommended Measures

On the front of the certificate is a table of the top actions you can take to save money and to make your home more efficient.

This is a summary of the full list of recommendations that are shown on page three.

The energy performance certificate explained part 6

Summary of Energy Performance

This table shows the different factors in the property that are assessed for energy efficiency and is useful to review the areas of your property and how they were measured.

Each factor, such as, heating, lighting and insulation are measured by a five-star rating of energy efficiency. For example

  • A rated property has high performance glazing – 5 stars
  • G rated property has double glazing – 3 stars

The insulation of the property is measured by a thermal transmittance rating that indicates the heat loss through walls, floors and the roof. Any insulation in the property must be visibly inspected in the assessment to be included. If it can’t be accessed (for example, cavity wall insulation) then documentation of evidence must be produced.

If the certificate states ‘Assumed’, this means that the area could not be visibly inspected and there was no evidence of insulation, so the assessment is marked as not insulated (whether there is insulation, or not).

Air tightness is measured on all domestic properties and large extensions built since 2006 (Building Regulations Part L). An air permeability test of the property for leakage through walls, windows, doors and floors is an indication of energy efficiency. For all new dwellings since 2006, this is marked on the certificate but for all existing dwellings older than 2006 this isn’t included or required.

Underneath the table is the primary energy use per square metre that’s used in the calculation of the EPC rating. For example

  • A rated property – 15 kWh/m2 per year.
  • G rated property – 913 kWh/m2 per year.
The energy performance certificate explained part 7

Heat Demands

The heat demand table indicates how much energy is used to heat the space of the property and to heat the water And is measured based on a standard occupancy and usage.

For example

  • A rated – space heating – kWh per year – 5,371
  • G rated – space heating – kWh per year – 37,973

On the G rated property, the table also highlights how much impact having insulation in the property can make to the energy used in heating the space of the property.

The energy performance certificate explained part 8


The recommendations table is so important because it breaks down how much your EPC rating can be improved, what the costs to make the improvements are and as a result, how much of a saving you can make on your annual energy bill. This will help you to make an informed decision on what changes you should be making.

The lower the rating on the certificate, the more attention you should give to the recommendations section as this could make a significant difference to the value of a property.

The recommendations in the table are made in cumulative order, this means that in the table, the potential improvement rating shown in the right column is only applicable if all the improvements up to and including that row are made.

You’re not legally obligated to make changes recommended.

For example:

The G rated property has nine recommendations that could take the property from a G11 rating to a C76 – a huge increase of 65 points. But, to achieve this would be a cost of up to £51,640 to result in energy savings of £2,910 per year (payback of 18 years). Cost effective?

To take the property to an E rating and an increase of 38 points would be a cost of up to £12,640 resulting in energy savings of £1,870 (payback of 7 years). A more reasonable achievement and would take the property to the minimum rental rating.

The A rated property has one recommendation of solar water heating. At a cost of up to £6,000 this will only make savings of £51 and an improvement of one point to A96 on your EPC. Probably not an investment worth making.

The energy performance certificate explained part 9

Environmental Impact (CO2) Rating

In response to the Kyoto Protocol and the UK's commitment to reduce emissions, more awareness has been made about what contributes to climate change. As a quarter of all CO2 emissions in the UK come from the energy we use to heat and light our homes, the EPC is all about helping to reduce carbon emissions. The average house contributes about 6 tonnes of carbon dioxide every year.

The impact of buildings on the environment used to be shown on the front of the certificate alongside the EPC rating. This has now been moved to the last page, most likely because displaying the two graphs next to each other was confusing and also, the environmental impact rating had no context for most people.

As the overall focus of an EPC is about reducing emissions, the environmental impact is actually the most important rating on the certificate but has the least meaning to most people. A higher rating means that a property has less impact on the environment. For example:

  • The G Rated property has a 1-point (very low) rating and produces 21 tonnes of CO2 in a year.
  • The A rated property has a 94-point (very high) rating and produces 0.4 tonnes of CO2 in a year.

What Is a Good EPC Rating?

In England and Wales, there are just over 22 million domestic EPC certificates.

The average EPC rating for a property in England and Wales is a band D.

RatingNo. of domestic EPCsSAP Rating






Data up to the end of December 2021, source.

Information is correct at the time of publication: Updated June 2022.

This page is a guide only and not a source of legal information.

Commonly Asked Questions

  • +
    How do you get an Energy Performance Certificate?

    An EPC can only be issued by an accredited Domestic Energy Assessor. You can find a local, qualified assessor here through the EPC Register.

  • +
    What is the EPC register?

    The register is a list of all EPCs produced and you can search for an individual certificate either by reference number (shown on the certificate) or by the property address.

    If you want to check if a certificate is authentic or search for a property you can access the register here.

    Scotland has a separate register here.

  • +
    How much does a certificate cost?

    There is no set fee for an EPC and the price for a certificate to be issued can be as low as £50 or up to £120.

    As there is no variation to the certificate, there is no benefit from paying more for an EPC, so searching online will help you find a good deal. Going direct to an assessor is cheaper than through an estate agent – just make sure your assessor is accredited (using the register).

  • +
    How long is an Energy Performance Certificate valid?

    An EPC in England and Wales lasts for ten years unless major work has been undertaken at the property.

    You can have your property reassessed at any time, for example, you might have made energy efficiency changes and want the rating to reflect this.

    Note, that once you have a new certificate issued it supersedes all previous certificates. So, if your rating goes down you can’t use an older certificate, even if that has not reached the ten-year limit.

    You will be charged for every new certificate you have issued.

  • +
    Does a good EPC rating increase the value of my house?

    A certificate reflects investment in energy efficiency. This can be through:

    • Double or triple glazing.
    • An energy-efficient boiler.
    • Cavity wall and loft insulation.
    • Solar panels or renewable energy systems.

    If you have two houses on the same street of the same size, then a house that has double glazing, cavity wall insulation and a new condensing boiler will have a higher valuation than the house that has an old boiler, no central heating or single-glazed windows.

    Making a property more energy efficient is an investment in the infrastructure of the building and this will also increase its value.

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