Buildings requiring a DEC

A DEC and advisory report are required for buildings with a total useful floor area (see definitions at Annex B) over 250m² that are occupied in whole or part by public authorities and frequently visited by the public.

For the purposes of the regulations, a building is defined as, ‘a roofed construction having walls, for which energy is used to condition the indoor climate, and a reference to a building includes a reference to a part of a building which has been designed or altered to be used separately’^{[footnote 1]}.

For a building to fall within the requirement for a DEC it must:

• have a roof and walls; and
• use energy to condition the indoor climate. This is the case where the building has any of the following fixed services: heating, mechanical ventilation or air conditioning

A building can either be:

• the whole of a building; or
• part of a building, where the part is designed or altered to be used separately

Only buildings, with a total useful floor area greater than 250m², occupied by a public authority and frequently visited by the public are affected by this legislation.

Private organisations, including those that may share a building with a relevant institution, do not need to display a DEC, but may elect to do so on a voluntary basis.