Energy Performance Certificate: In-Depth Guide

Guide to the Energy Performance Certificate


The Energy Performance Certificate (EPC) rates the energy efficiency of a domestic dwelling.

Following assessment, properties are rated on a scale. A is the higest rating, meaning a property is highly energy efficient and G is the lowest and least energy efficient.

The average EPC rating for the UK is band D. Rental properties must achieve a rating of band E or higher.

Read our in-depth guide below, including What is an EPC? and How you can improve your EPC rating 

EPC Map for England and Wales

Showing the most/least energy efficient properties by local authority

England & Wales


  • Pop. -
  • Total EPC -
Number of EPCs: ACTUAL %

(Click on map for detailed information about each area)

What is an energy performance certificate (EPC)?

To really understand the motivation behind the EPC, we need to go back to 1997, when The Kyoto Protocol was signed. The international treaty was a pledge and an objective to reduce greenhouse gasses "to a level that would prevent dangerous anthropogenic interference with the climate system" (Article 2).

As a result, in 2002, the European Union (EU) approved the Energy Performance of Buildings Directive (EPBD) that was to be introduced for all EU member states by 2006. Article 7 of the directive required the introduction of an Energy Performance Certificate (EPC) for buildings.

In the UK, the the Home Information Pack (HIP or Hip) was introduced in England and Wales in 2007. It required anyone selling a property to pay for a bundle of information before they could put their house on the market; including an energy performance certificate. The idea was that HIPs would reduce the time to process selling a house but instead drew much criticism in the industry for stalling housing sales by putting off sellers from ‘testing the market’. Subsequently, HIPs were discontinued in 2010.

After the demise of HIPs, the EPC continued as a requirement for sellers and for landlords of rented property.

"For buildings offered for sale or rent, the energy performance certificate shall be stated in advertisements" EPBD 'Recast', 2010

EPBD was superseded with a revised version in 2010 but the emphasis remained on all buildings either for sale or rent, to provide an energy performance certificate before the property is marketed.

In 2018, the Government announced that landlords are required to make their properties more energy efficient by the end of 2019. A rented property has to achieve a rating of ‘E’ or higher on the EPC scale before it can be leased to a tenant or the landlord will face a fine.

"These changes are expected to save households an average of £180 a year while reducing carbon emissions and potentially increasing property values with analysis showing the cost to the landlord would be more than offset by the increase in property value.” UK Government

The minimum rating for rental properties and the commitment by the UK to address the energy efficiency of buildings, indicates that in the near future there’s a real possibility that all properties will have to reach minimum EPC ratings. For any homeowner, it’s in their interest to do all they can now to achieve a high EPC rating – to ensure their property is more desirable for sale and to benefit from a higher valuation.

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

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.

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.

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.

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).

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.

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.

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 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. If you should ever want to rent out your property, it must be a minimum of an E rating.

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.

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.

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 – the EPC rating must be band E or above.
  • 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

Common questions asked about EPCs…

Click to expand

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 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).

The price for a certificate to be issued can be as low as £50 or up to £120.

How long is an Energy Performance Certificate valid for?

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.

What is a good EPC rating?

In England and Wales, there are 6.1 million D rated properties and 4.1 million C rated. At the bottom of the scale, 239,000 have the lowest G rating whilst only 19,000 have a top rated A. The average EPC rating for a property in England and Wales is a band D.

View our map to see which regions have the highest and lowest rated properties.

As there are already guidelines for rental properties to be in band E, it’s possible that in the near future there will be minimum ratings for all dwellings. Therefore, achieving as high as score as possible for your property is essential.

Aside from ratings, what’s important is the reason that the EPC exists and that’s to reduce emissions by reducing energy consumption. The more highly rated your property is, the more savings you will make on energy bills – and that really should be every householder’s objective.

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.

How can I improve my EPC rating?

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Loft insulation is easy to install, is unintrusive, is relatively inexpensive and can help to retain a quarter of household heat which is lost through the roof. For the significant difference it can make to your EPC score, it’s one of the easiest ways to add several points.

A 270mm minimum depth of rock wool insulation is recommended.

Cavity wall insulation is the process of filling the cavities inside your external walls by injecting polystyrene beads or by installing mineral wool and is relatively inexpensive and easy to complete. As a third of heat is lost through uninsulated walls, this process will make a difference to the energy efficiency of your home.

Most houses built after 1990 are already insulated but a house built between 1920 and 1990 will most likely have cavity walls that may need insulating.

There is a caveat that not all buildings are suitable for cavity wall insulation, as it can result in problems with damp and mould and this can affect people’s health. The most unsuitable buildings are those exposed to excessive wind and rain (mainly in the West) and we recommend seeking advice to find out if your property is suitable. There is a useful map here.

It's vital to find a reputable supplier, as poorly fitted cavity wall insulation can be incredibly costly to fix.

Note, that you will have to provide evidence of the insulation during an assessment. An assessor will need to either visibly see the insulation or be provided with documentation that the insulation has been installed.

A G-rated semi-detached house can make savings of:

  • Roof insulation £252 per year
  • Cavity wall insulation £726 per year

Solid wall insulation is used to improve the thermal property of a solid wall. Houses built before 1920 are usually solid wall. It involves cladding the external walls and covering in render, and/or cladding internal walls with insulating material. This does require moving radiators and sockets, and so it’s both intrusive and a large investment.

Hot-water cylinder insulation – if you have an old hot water cylinder, then lagging with a cylinder jacket will retain the heat for longer and could save £20 a year. The connecting hot pipes can also be protected with foam tubes and these can be bought from any DIY store.

Double Glazing

Double glazing

Windows are responsible for up to 40% of heat loss in the home. Therefore, by replacing old windows with high performance glazing, you can make considerable savings on energy consumption by reducing heat loss.

To understand what the independent ratings for different windows and glazing mean, this page explains what to look for in an energy-efficient window.

Not only do windows have thermal properties, they also benefit from soundproofing (but this isn’t relevant to your EPC rating).

As glass loses more heat than a solid wall, a conservatory will lose a considerable amount of heat and should not be heated – to avoid excessive energy consumption. If the conservatory has a door into the main house that can be closed, then the conservatory space can act as a layer of insulation in the colder months.

If you live in a listed building, you may not be able to replace windows with double glazing but you can add secondary glazing – not as efficient but it does make a small difference.



Lighting has been impacted significantly since 2009 by the EU Directive with bans on certain types of bulbs, which 64% of householders are unaware of. The aim is to reduce the 19% global consumption of energy by lighting.

Not so long ago, all houses were lit with the traditional incandescent bulb but they began to be phased out in 2009 and are now banned from sale in the UK.

Halogen downlights embedded in ceilings became hugely popular, with an estimation that the average UK household has 10 halogen bulbs. Not as efficient as LED, halogens only have a working life of two years (at three hours per day use) by delivering bright spotlights.

Since 2018, halogen bulbs have now been removed from sale across Europe with a drive to pushing households to more energy-efficient choices.

Bulb choices for sale are now limited to LEDs and compact fluorescent lamps (CFLs) and all households will have to upgrade their lighting as old bulbs expire.

The benefit of swapping ten halogen bulbs to LEDs will equal a saving of £112 a year over a long-term period, according to Philips lighting manufacturer. Halogens only have a working life of two years, whilst an LED can last 20-30 years delivering considerable savings over the long term.

An old incandescent style 100W bulb costs £20 a year to run, in comparison to an LED bulb at only £5 a year.

When buying new bulbs, LED are sold in lumens as compared to wattage: a traditional 100W bulb is equivalent to a 13.5WLED and a traditional 75W bulb is equivalent to an 8.5W LED.



As heating equates to 55% of your energy bills, this is the area where changes can have a significant impact.

The EPC rating is measured on the unit cost of energy (and the CO2 emissions to produce the fuel) supplied to the heating system and not necessarily what’s a more efficient means of heating in individual circumstances. For example, a large open space is cheaper to heat with a point-of-source heater, such as a portable electric convector, rather than trying to heat the entire space with gas central heating.

In terms of gas versus electric, a gas central heating system will always score higher because it’s a cheaper unit of energy and has fewer emissions. An up-to-date gas combi-boiler will provide the highest EPC rating and if you can install a gas central heating system, then this is the best option.

Electric heating systems lose out because they are more expensive per kW to heat a property, even though in many cases they are more efficient at point of source and ultimately offer a cheaper bill.

Modern convector heaters, which may be more practical, are considered the least efficient because they use the highest rate of electricity and cost the most per unit of energy to run (three times as expensive as gas and more expensive than Economy 7).

Storage heaters, are rated higher than convectors purely because they benefit from night-time cheaper tariffs even though they aren’t always the most efficient solution and aren’t always practical for delivering heat when it’s needed. Usually, a property needs to rely on an alternative form of heating in the evenings once the storage heater runs cold. But, for EPC purposes, a modern smart storage heater will get a better rating if you have to rely on electricity based heating.

A G-rated, semi-detached house can make savings of:

  • Installing high heat retention storage heaters - £657 per year

Main heating controls

For those that have gas central heating, the use of thermostatic radiator valves on each individual radiator are a cheap investment and a quick win to improve your EPC rating.

Using a room thermostat will also better manage your energy usage and will have a positive influence on your rating.

Boiler replacement

Replacing an old boiler can have a significant impact on the energy efficiency of your heating and your EPC rating.

Replacing an old, G-rated (appliance rating) boiler that has less than 70% efficiency, with a new, A-rated condensing boiler with a programmer, room thermostat and thermostatic radiator controls, can make an annual saving of £305 for a detached house.

Renewable Energy

Renewable energy

The installation cost for renewable energy sources such as solar panels, ground-source heat pumps or biomass boilers can be prohibitive but the investment will deliver much lower energy bills, reduce carbon dioxide emissions and will also benefit from an increased EPC rating.

In an ideal world, all energy would be supplied from wind farms and solar panels and the UK has a target of renewable energy sources delivering 15% of all energy by 2020.

For an individual property, installing solar panels to harvest sunlight can heat hot water systems. Ground-source heat pumps, that extract natural warmth from the Earth, can efficiently heat a home.

There is no doubt that if installation costs were not an issue, this would be the best option for any property. To achieve the highest EPC ratings a property would require some form of renewable energy.

A G-rated, semi-detached house can make savings of:

  • Installing solar water heating - £135 per year
  • Installing solar panels - £311 per year
  • Installing a wind turbine - £594 per year