Display Energy Certificates (DECs) are a visual representation (on a scale of A-G) and show the actual energy usage of a public building (the Operational Rating) based on annual consumption figures.
A DEC allows the public to see the energy efficiency of the building and is based on the energy consumption of the building as recorded by gas, electricity and other meters. The DEC should be displayed at all times in a prominent place clearly visible to the public and is always accompanied by an Advisory Report that lists cost-effective measures to improve the energy rating of the building.
DECs are only required for public buildings with a total useful floor area greater than 1,000m2, that are occupied by a public authority or an institution providing a public service to a large number of people, and are frequently visited by members of the public. DECs are valid for one year. The accompanying Advisory Report is valid for seven years.