A Display Energy Certificate (DEC) and an Advisory Report (AR) are required for any building with a total useful floor area in excess of 1,000m², occupied, or part occupied, by a public authority or institution, providing a public service to a large number of people and is therefore visited by those people. It is the responsibility of the public authority or organisation to prepare and display a DEC and have an AR in place.  DECs are required from 1st October 2008 to be displayed in a prominent position, clearly visible to all visitors to the site and an AR must be in place. The DEC will need to be renewed annually and the AR every seven years.