Display Energy Certificates (DECs) were introduced as a requirement for buildings occupied by a public authority as part of the implementation in England and Wales of the European Directives 2002/91/EC and 2010/31/EU on the energy performance of buildings.
Originally the requirement was for buildings larger than 1,000m², however this was later reduced to 500m² and from 9 July 2015 has applied to any public authority occupied building larger than 250m² and frequently visited by the public.
The purpose of DECs is to raise public awareness of energy use and to inform visitors to public buildings about the energy use of a building. They display to the visiting public how well (or not) the energy efficiency of the building is managed. DECs are a highly visible way of making the public sector accountable for how wisely it spends the public’s money.
DECs provide an energy rating of the building from A to G, where A is the most efficient, and G is the least efficient. They are based on the actual amount of energy used by the building over the 12 months preceding the validity period of the DEC.
An affected organisation must display a DEC in a prominent place clearly visible to the public and have in its possession or control a valid advisory report. The advisory report contains recommendations for improving the energy performance of the building.
A DEC and recommendations report are required for buildings with a total useful floor over 250m², which are occupied in whole or part by public authorities and which are frequently visited by the public. A building in the context of these regulations includes a part of a building which has been designed or altered to be used separately.