Energy performance certificates are required to meet the European energy performance of buildings directive - EPBD. The EPC (domestic) is a mandatory requirement for inclusion in the home information pack. EPC will identify an individual's property within an energy rating between 1 and 100.

EPC will give typical fuel costs of carbon dioxide (CO2) emissions for that particular property. This EPC and subsequent rating is intended to identify energy efficiency of that property and environmental impact.

Our homes account for 27% of the United Kingdom's carbon emissions, contributing to global climate change. It is estimated that following the recommendations in an energy performance certificate, an average of £300 a year can be saved in fuel bills.The certificate will make recommendations for cost-effective improvements to help cut fuel bills and carbon emissions.

Commercial properties and public buildings currently account for nearly 25% of the UK's carbon emissions, contributing to global climate change. EPC (Commercial) certificate is intended to give an estimate of CO2 emissions of a building and is based upon an asset rating system. It indicates the energy efficiency of the building fabric and HVAC system. This system does not take into consideration the actual usage of the property, but makes certain assumptions with regard to current usage in order to allow comparison between different buildings of the same type. The intention is that prospective purchasers or tenants can easily compare one commercial building to another of similar type when considering which is more suitable prior to a purchase or lease.

By 1 October 2008 public sector occupiers of certain public buildings will need to have a Display Energy Certificate (DEC) in a prominent place where it is clearly visible to the public, unless there are exceptional circumstances. They will also need to have in their possession a valid Advisory Report (AR).

Only buildings occupied or part occupied either by a public authority or an institution providing a public service to a large number of people and who are therefore frequently visited by those people, and with a total useful floor area greater than 1000m2 are affected by this legislation. A DEC must contain, by law, the following information:

• The operational rating and the asset rating (if available) as determined by the government approved method.
• Show the operational ratings for the building expressed in any certificates displayed by the occupier during the last two years before the nominated date.
• Include a reference value such as a current legal standard or benchmark.
  

The DEC will also show the unique certificate reference number, the address of the building, the total useful floor area of the building, the name of the energy assessor, their employer (or trading name if self employed), the name of their accreditation scheme and the date when the DEC was issued. The DEC must be accompanied by an Advisory Report. DECs are valid for 12 months, advisory reports for 7 years.