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EPC vs DEC Energy Certificates | The Requirements

Andrew Sadler

Sustainability and building compliance expert. Specialising in low energy design, SAP, SBEM, BREEAM, and air testing for the construction industry,

Andrew Sadler

May 8, 2018

We recently had a client asking what the difference between and Energy Performance Certificate (EPC) and Display Energy Certificate and do you need one if you have the other. So we looked into it further.


What is an Energy Performance Certificate?

The Energy Performance of Buildings Regulations came into effect on the 1st August 2007 with the requirements of various types of building being phased in. The first phase introduced the requirement to be produced on the sale of homes (marketed sales only). At the end of 2008 the requirements were increased to include all homes when sold, all homes when rented and all remaining non-domestic buildings when sold, built and rented.

An Energy Performance Certificate is used to demonstrate the deficiency of the property based on a pre defined usage pattern depended on the building type and building size. This is used to allow potential building owners and occupiers to compare one building to another. A building with a EPC rating of ‘A’ will be expected to perform in a more efficient way than a building with a rating of ‘B’. Find out more about our Energy Performance Certificate.

What is an Display Energy Certificate?

As of 1st October 2018 buildings occupied by public authorities over 1,000 m3 where they are frequently visited by the public must display a Display Energy Certificate at all times. The Energy Performance of Buildings Regulations was updated and DECs are now require all public buildings over 250m2. Unlike buildings large than 1,000m2, which require a new DEC on an annual basis, these certificate are valid for 10 years. Public authorities mus have a DEC for a building of all the following are true:

A DEC is used to display how much energy the building is actually using “in use” over the previous twelve month period.

On other words a EPC shows the theoretical efficiency of a building, whilst an DEC shows the actual energy performance of the building.

Do we need both a DEC and EPC?

As discussed above both certificates perform a different purpose and represent different information. As such an EPC is required on construction, sale or rental of a property irrespective of the existence of a Display Energy Certificate.


Contact us now to discuss your project requirements.

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