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. This is based on the energy consumption of the building as recorded by gas, electricity and other meters. The DEC should be clearly displayed at all times and be clearly visible to the public. A DEC is always accompanied by an Advisory Report that lists cost effective measures to improve the energy rating of the building.

Display Energy Certificates are currently required for buildings with a total useful floor area over 500m2 that are occupied by a public authority or institution providing a public service to a large number of persons and therefore visited by those persons. They are valid for one year. The accompanying Advisory Report is valid for seven years.

The legal requirement for Display Energy Certificates came into effect on 1 October 2008.

Eta Energy Systems ltd employ accredited Low Carbon Consultants under the CIBSE accreditation scheme to produce DECs and ARs.