Large Public Sector buildings must display a DEC. A Display Energy Certificate shows the energy performance of a building based on actual consumption as recorded annually.

These are to raise public awareness of energy efficiency in public buildings. DECs provide an energy rating of the building from A to G, where A is very efficient and G is the least efficient and they are based on the actual amount of metered energy used by the building over a period of 12 months. They also show ratings for the previous 2 years for comparison.

EBSNI Ltd provide DECs and recommendation reports indicating the buildings energy performance and potential ways to improve efficiency.