Display energy certificates and advisory reports for public buildings

All non-domestic buildings with a useful floor area over 250m2 and regularly visited by the public require a Display Energy Certificate (DEC). A DEC is produced by comparing twelve months of meter readings to a benchmark for a typical but hypothetical building. The reason DECs were introduced into law is so visitors to a building can be informed about the building’s energy usage.


The energy performance of a building in a DEC is calculated to give a number on a scale of one to a hundred and placed in a group rating between ‘A’ and ‘G’. Follow this link to see an example of a DEC for a public building.

The A to G energy consumption label is also used throughout Europe on white goods, cars and light bulbs. The following link provides more information on EU energy labelling.

In an ideal world, all DECs would have an A+ rating. An Advisory Report (AR) could accompany the DEC and provide recommendations for improving the DEC grade. The DEC rating could rise by improving the building fabric, upgrading the building services and/or installing low or zero carbon technologies.

A DEC is valid for 12 months if the building has a total useful floor area of more than 1000m2 and an accompanying AR is valid for seven years. If the building has a total useful floor area between 250m2 and 1000m2, the DEC and AR are both valid for ten years.

More information

The follow link will take you to a guide to DECs and ARs produced by The Department for Communities and Local Government and to help answer any questions you may have, the Milton Keynes Council Sustainability Team has produced an online question and answer factsheet.

DECs and ARs must be produced in an approved method by an accredited energy assessor. The documents must be lodged on the National Register and given a unique reference number.

Milton Keynes Council can provide DECs and ARs by accredited assessors.

If you would like to enquire about a DEC and AR for your building or require further information, please send an email to carbon@milton-keynes.gov.uk