The energy survey needed to produce an EPC is performed by an assessor who visits the property, examines key items such as loft insulation, domestic boiler, hot water tank, radiators, windows for double glazing, and so on. He or she then inputs the observations into a software program which performs the calculation of energy efficiency. The program gives a single number for the rating of energy efficiency, and a recommended value of the potential for improvement. There are similar figures for environmental impact. A table of estimated energy bills per annum (and the potential for improvement) is also presented, but without any reference to householder bills. The householder will have to pay for the survey, which costs around £60 for a four bedroom house. The exercise is entirely non-invasive, so the software will make assumptions on the insulation properties of various elements of the property based on age and construction type. The assessor has the ability to over-ride these assumptions if visual or written evidence is provided to support the presence of insulation which may have been subsequently installed.
The calculation of the energy ratings on the Energy Performance Certificate (EPC) are based on the RDSAPv3 procedure, which is a simplified version of the SAP2005. SAP is short for Standard Assessment Procedure and RDSAP for Reduced Data SAP; both are derived from the UK Building Research Establishment's Domestic Energy Model (BREDEM), which was originally developed in the 1980s and also underlies the NHER Rating. EPCs have to be produced by domestic energy assessors who are registered under an approved certification scheme.
The certificate contains the following property details:Property address
Property type (for example detached house)
Date of inspection
Certificate Date and serial number
Total floor area
The total floor area is the area contained within the external walls of the property. The figure includes internal walls, stairwells and the like, but excludes garages, porches, areas less than 1.5 m high, balconies and any similar area that is not an internal part of the dwelling.
Energy Performance Certificates present the energy efficiency of dwellings on a scale of A to G. The most efficient homes – which should have the lowest fuel bills – are in band A. The certificate uses the same scale to define the impact a home has on the environment. Better-rated homes should have less impact through carbon dioxide (CO2) emissions. The average property in the UK is in band D or E.
The EPC will become more significant from April 2014 when Domestic Renewable Heat Incentives (RHI) become available. The amount of the deemed expected annual heat use for a domestic property can be obtained from the EPC and this will determine the amount of Domestic RHI which is payable on installing renewable heat options like ground source heat pumps and solar thermal collectors.
The certificate includes recommendations on ways to improve the home’s energy efficiency to save money. The accuracy of the recommendations will depend on the inspection standards applied by the inspector, which may be variable. Inspectors, who may be Home Inspectors (HIs) or Domestic Energy Assessors (DEAs), are audited by their accreditation bodies in order to maintain standards. The recommendations appear general in tone, but are in fact bespoke to the property in question. The logic by which the RDSAP program makes its recommendations was developed as part of a project to create the RDSAP methodology, which took place during the early years of the 21st century. The EU directive requires the EPC recommendations to be cost effective in improving the energy efficiency of the home, but in addition to presenting the most cost effective options, more expensive options which are less cost effective are also presented. To distinguish them from the more cost effective measures, these are shown in a section described as 'further measures'. Because the EPC is designed to be produced at change of occupancy, it must be relevant to any occupier and it therefore must make no allowance for the particular preferences of the current occupier.
Properties exempt from the Housing Act 2004 are:Non-residential, such as offices, shops, warehouses.
Mixed use, a dwelling house which part of a business (farm, shop, petrol station)
Unsafe properties, a property that poses a serious health and safety risk to occupants or visitors
Properties to be demolished, properties that are due to be demolished where the marketing of the property, all the relevant documents and planning permission exists.
Listed buildings (Recast of EPC requirements from 9 January 2013)
Stand alone buildings of less than 50m2 (Recast of EPC requirements from 9 January 2013)
Buildings of religion or worship (Recast of EPC requirements from 9 January 2013)
Residential buildings with use of less than 4 months per year (Recast of EPC requirements from 9 January 2013)
In addition to the requirements in relation to dwellings there is also a requirement for EPCs on the sale, rent or construction of buildings other than dwellings with a floor area greater than 50m2 from 6 April 2008, that contain fixed services that condition the interior environment.
Properties that are exempt from requiring a domestic EPC will generally require a non-dwelling energy performance certificate, which was also required by the Energy Performance of Buildings Directive. Non-dwellings are "responsible for almost 20 per cent of the UK’s energy consumption and carbon emissions."
All non-dwelling EPCs must be carried out by, or under the direct supervision of, a trained non-domestic energy assessor, registered with an approved accreditation body. DCLG has arranged for a publicly accessible central register of such assessors maintained by the Landmark Information Group.
There are three levels of building, Level 3, Level 4 and Level 5. The complexity and the services used by that building will determine which level it falls under.
A Commercial Energy Assessor must be qualified to the level of the building to carry out the inspection
From October 2008 all buildings including factories, offices, retail premises and public sector buildings - must have an EPC whenever the building is sold, built or rented. Public buildings in England and Wales (but not Scotland) also require a Display Energy Certificate showing actual energy use, and not just the theoretical energy rating. From January 2009 inspections for air conditioning systems will be introduced.
The A to G scale is a linear scale based on two key points defined as follows:
a) The zero point on the scale is defined as the performance of the building that has zero net annual CO2 emissions associated with the use of the fixed building services as defined in the Building Regulations. This is equivalent to a Building Emissions Rate (BER) of zero.
b) The border between grade B and grade C is set at the Standard Emissions rate (SER)† and given an Asset Rating of 50. Because the scale is linear, the boundary between grades D and grade E corresponds to a rating of 100.
†This is based on the actual building dimensions but with standard assumptions for fabric, glazing and building services.
See an example.
Display Energy Certificates (DECs) show the actual energy usage of a building, the Operational Rating, and help the public see the energy efficiency of a building. This is based on the energy consumption of the building as recorded by gas, electricity and other meters. The DEC should be clearly displayed at all times and clearly visible to the public. A DEC is always accompanied by an Advisory Report that lists cost effective measures to improve the energy rating of the building.
Display Energy Certificates are only required for buildings with a total useful floor area over 500m2 that are occupied by a public authority and institution providing a public service to a large number of persons and therefore visited by those persons. The useful floor area limit will be reduced to 250m2 in July 2015.
Where the building has a total useful floor area of more than 1,000m2, the DEC is valid for 12 months. The accompanying advisory report is valid for seven years. Where the building has a total useful floor area of between 500m2 and 1000m2, the DEC and advisory report are valid for 10 years.
However, to make it easier for public authorities with multiple buildings on one site to comply with the legislation, a site-based approach for the first year (to October 2009) is allowed where it is not possible to produce individual DECs. This means that only one DEC will need to be produced based on the total energy consumption of the buildings on the site. Public bodies most affected by this relaxation are NHS Trusts, universities and schools.
The requirement for Display Energy Certificates came into effect from 1 October 2008. They were trialled in the UK under an EU-funded project also called "Display" and co-ordinated by Energie-Cités; participants included Durham County Council and the Borough of Milton Keynes.
This is the Operational Rating for this building. The rating shows the energy performance of the building as it is being used by the occupants.
A building with performance equal to one typical of its type would therefore have an Operational Rating of 100. A building that resulted in zero CO2 emissions would have an Operational Rating of zero, and a building that resulted in twice the typical CO2 emissions would have an Operational Rating of 200.
This rating indicates whether the building is being operated above or below average performance for a building of this type.
See an example.
EPCs have gained some political controversy, partly reflecting the housing market crisis in the United Kingdom (2008).
Many in the housing industry, such as the Royal Institution of Chartered Surveyors, have criticised the introduction of EPCs, on the grounds of poor quality.
A further objection is often made concerning the quality of inspection made to produce the certificate. It cannot be invasive, so the inspector cannot drill walls or ceilings to determine the state or even existence of any insulation. He or she can either assume the worst (no insulation present) or rely on the householder (who may know about the matter). This can produce uncertainty about the validity of the output from his or her analysis.
Finally, EPCs pose particular problems for the owners of listed buildings, as improvements, such as double glazing, are often barred by the controls on changes to such structures, making it difficult to rectify low ratings. From 2013, EPCs are no longer required for listed buildings.