| The requirement for Display Energy Certificates came into effect on 1 October 2008. |
| Only buildings with a total useful floor area over 1000m 2 that are occupied or part occupied either by public authorities or by institutions providing public services to a large number of people and therefore visited by those persons are affected by this legislation. |
| Where a building is partly occupied by a public authority or a relevant institution, the authority or institution is responsible for displaying a DEC and having a valid advisory report. Other private organisations occupying the building, irrespective of the size they occupy, do not need to display a DEC. |
| 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. It is based on the energy consumption of the building as recorded by gas, electricity and other meters. The results of the energy rating are from A to G (A being the most efficient). A DEC is different to an EPC as it shows the energy performance of the building based on actual metered consumption. The purpose of a DEC is to raise public awareness of energy consumption. |