The Display Energy Certificate (DEC) rating is based on the measured, actual energy use of a building. This is then compared to a benchmark for similar buildings. In contrast, a BER is based on calculated energy use.

The certificate shows the grade awarded, energy and CO2 performance indicators, and your energy trends. It is required in addition to the BER and covers both privately and publicly owned large buildings.

Buildings requiring a DEC

• a building other than a dwelling, which is occupied by a public body, has a total useful floor area greater than 250 m2, and is frequently visited by the public
• a building other than a dwelling, which has a total useful floor area greater than 500 m2, and is frequently visited by the public