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Domestic Energy Assessors

EPC Information

Learn about an EPC.

Why are domestic properties being rated for energy efficiency?

It is internationally recognised that the accumulation of specific gases in the atmosphere contribute to a “greenhouse” effect on the temperature of our planet. This is considered to be changing climatic conditions and weather patterns worldwide.

Carbon dioxide, which is produced when fossil fuels (coal, natural gas and oil) are burned for energy, is a significant one of these gases. In 1997, many countries around the world signed up to the Kyoto Protocol, which agreed a set of measures to reduce C02 emissions. 

One of the highest areas of energy consumption is in heating our homes.

As buildings overall are responsible for almost 50 % of all energy consumed in the UK, it is vital that we make them more energy efficient.

Following extensive analysis of the whole energy issue, the EU and UK Government began to formulate a strategy to deal with the problems.

Communities and Local Government is leading the introduction of a number of energy and cost savings measures to make all buildings more efficient. The measures are being applied across all European Union countries and are in line with the European Directive for the Energy Performance of Buildings (EPBD).

What’s Being Done?

To help to tackle the problem, all new homes constructed are now built with minimum standards of energy efficiency.

However, many of the approximately 25 million dwellings in the UK were built many years ago, when less importance was placed on thermal efficiency. At the forecast rate of building, a large proportion of current buildings will still be in regular use in 2050, so improving the performance of existing buildings is a particular priority. Consequently, these dwellings need to be individually assessed and rated as of today.

Housing Act legislation has been introduced that requires a residential dwelling to have an Energy Performance Certificate (EPC) prepared by a suitably qualified and licensed Domestic Energy Assessor (DEA), whenever it is rented out or marketed for sale. Accreditation schemes ensure that the public can feel comfortable that the individuals completing Energy Assessments in their home can be trusted and will operate in a professional manner.

The results are made available to the owner and prospective purchasers or tenants of the property, as a mandatory document within Home Information Packs (England & Wales) that were introduced on 1st August 2007. Information Packs have since been withdrawn, but the EPC is still a key part of all transactions. All current EPC’s can be searched by postcode and viewed on the national database at www.epcregister.com where many FAQ’s can are answered. https://www.epcregister.com/faq.html

How this has been phased-in:

  • 1 August 2007 EPC's required (within a HIP) for the marketed sales (and leaseholds) of existing dwellings with 4 or more bedrooms.

  • 10 September 2007 EPC's required (within a HIP) for the marketed sales (and leaseholds) of existing dwellings with 3 or more bedrooms.

  • 14 December 2007 EPC’s required (within a HIP) for the marketed sales (and leaseholds) of all existing dwellings.

  • October 2008 EPC’s required for rental of all dwellings and all remaining sales and leaseholds of dwellings. This includes non-HIP's marketed sales and all non-marketed sales.

  • April 2018 Minimum Energy Efficiency Standard (MEES) introduced for domestic lettings. All subsequent tenancies must be in dwellings higher than F & G ratings.

EPC’s are one of the innovative methods for increasing awareness of the need to reduce energy consumption in buildings. The idea is similar to the well-known energy labels for the sale of white goods such as fridges and washing machines. Its purpose is to record how energy efficient a property is as a building. The certificate will provide a rating of the energy efficiency and carbon emissions of a building from A to G, where A is very efficient and G is very inefficient.

Whether or not a property ultimately sells, implementation of all or some of the recommended improvement measures will contribute to reducing carbon dioxide emissions, cut domestic heating bills, and increase the level of comfort within the home.

How an EPC is calculated

EPC's are produced using standardised methods using some common assumptions, so that the energy efficiency of one building can easily be compared with another.

This allows prospective buyers, tenants, owners, occupiers and purchasers to see information on the energy efficiency and carbon emissions from their building so they can consider energy efficiency and fuel costs as part of their investment.

SAP is the Government's Standard Assessment Procedure for energy assessments of dwellings. The current version of SAP, SAP 2012, has been adopted by Government as part of the England and Wales national methodology for calculation of the energy performance of buildings. It is used to demonstrate compliance for dwellings with Part L of the Building Regulations 2000 (in England and Wales). For further information visit: BRE SAP 2012

RdSAP (Reduced Data Standard Assessment Procedure) is the new Government-approved standardised assessment procedure for energy assessments of existing dwelling. A full SAP assessment requires many data items that cannot be seen in a survey (or take too long to collect). RdSAP is an industry-agreed standard set of data items and a standard way of inferring the missing data using default values wherever necessary.

On site, the DEA will need to take measurements of the overall “footprint” of the dwelling and determine the degree of heat loss through the various elements of construction. A floor plan is produced to assist with calculations and provides a concise and permanent record. Additionally, the height of each floor level is required to determine the volume of air to be heated.

View data collection to see a sample selection of other data that has to be collected in order to calculate the EPC.

What does a finished EPC contain?

Sample EPC pdf for homes, two ratings are shown.

The energy-efficiency rating is a measure of a home's overall efficiency. The higher the rating, the more energy-efficient the home is, and the lower the fuel bills are likely to be.

The environmental impact rating is a measure of a home's impact on the environment in terms of carbon dioxide (CO2) emissions - the higher the rating, the less impact it has on the environment.

Each rating is based on the performance of the building itself and its services (such as heating and lighting), rather than the domestic appliances within it. This is known as an asset rating. The ratings will vary according to the age, location, size and condition of the building. The potential rating on the certificate will take these factors into account, and the suggested measures will be tailored so that they are realistic for the particular building.

In addition to the asset ratings, EPC's must convey several other key pieces of information:

Reference information

This includes the type of property (e.g. house, flat), the unique reference number (as stored in the central register) and date of the certificate.

Estimated energy use

This is based on standardised assumptions about occupancy and heating patterns. An estimate of the current and potential energy use, carbon emissions and fuel costs for lighting, heating and hot water is provided. The actual energy use depends on the behaviour of the occupants.

Energy Assessor details

This includes the assessor's name, accreditation number, company name (or trading name if self employed) and contact details.


The certificate will provide information about how to complain or how to check the certificate is authentic.

Energy advice

The certificate provides basic advice about energy efficient behaviour.

Recommendation report

An EPC is accompanied by a recommendations report that lists measures (such as installing low and zero carbon generating systems) to improve the energy rating of the building. The certificate is also accompanied by information about the rating that could be achieved if all the recommendations were implemented. Recommendations include low cost improvements and further improvements (that achieve higher standards but are not necessarily cost effective). For each improvement the level of cost, typical cost savings per year and the performance rating after improvement are listed in this PDF. The potential rating shown on the certificate is based on all the recommendations being implemented.