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What are Display Energy Certificates (DEC)?

A Display Energy Certificate also called a DEC, shows the energy performance of a building based on actual energy consumption as recorded over the last 12 months within the validity period of the DEC (the operational rating). The operational rating is a numerical indicator of the actual annual carbon dioxide emissions from the building.
The various types of energy consumption from occupying a building must be brought together on a common basis so that the performance of one building can be compared with that of another. The UK has decided that the common unit should be CO2 emissions, since this is a key driver for energy policy.

This rating is shown on a scale from A to G, where A is the lowest CO2 emissions(best) and G is the highest CO2 emissions (worst).

DECs for buildings larger than 1,000m² also show the operational ratings for the previous two years where available.

The operational rating of a DEC is based on the amount of energy consumed during the occupation of the building over a period of 12 months from meter readings and is compared to a hypothetical building with performance equal to one typical of its type (the benchmark).

Typical performance for that type of building would have an operational rating of 100. A building that resulted in zero CO2 emissions would have an operational rating of zero, and a building that resulted in twice the typical CO2 emissions would have an operational rating of 200. If the building is a net energy generator, it would still be given an operational rating of zero.

The DEC should be displayed in a prominent place that is clearly visible to members of the public. A sample certificate is shown.

Display Energy Certificate DEC



To enable members of the public to view the document easily, it should be no smaller than A3 in size.

A DEC must be accompanied by an advisory report and the owner of the building must have a valid one available. The advisory report highlights recommendations to improve the energy performance of the building (i.e. its fabric and associated services such as heating, ventilation and lighting).

Responsibilities for displaying a DEC

Under this legislation it is the responsibility of every occupier of a building affected by these regulations to:

•Display a valid DEC in a prominent place clearly visible to the public at all times •Have in their possession or control a valid advisory report which conveys recommendations to improve the building’s energy performance

This must be done for each of the buildings affected

An energy assessor, accredited to produce DECs, is the only person who can produce a DEC and advisory report for your building. We can provide you with a qualified person who belongs to one of the accreditation bodies,fully covered for personal indemnity insurance.


Get a Quote from us

Each job we take, we will quote according to the complexity of the building or buildings concerned. The price with therefore be reflected by this. You can either fill out our contact form (see link on this page) or email us direct with your information. If you need help and guidance please feel free to phone us on 01323 841488 or 07867 960 711. Our Energy Assessment Manager will help you with anything you need assistance with.