An EPC is only required for a building when constructed, sold or let.
The certificates for the sale or letting of buildings other than dwellings, will be valid for ten years provided no major changes are made to the structure or services of the building.
A building will require an EPC if it has a roof and walls, and uses energy to condition the indoor climate (heating, mechanical ventilation or air conditioning).
If selling or letting a building as a whole, one EPC can be provided for the whole building, even if the building is divided into separate parts with separate heating systems.
Should a seller / landlord wish to sell or let a part of a building where the whole building has a common heating system, they have a choice to either provide an EPC for the whole building or just a part designed or altered to be used separately.
In the latter case, the assessment should be based on energy use per square metre for the whole building.
In the case of buildings with separate parts and separate heating systems, an Energy Performance Certificate should be provided for each part of the building that is being offered separately for sale or let.
The action of selling or letting triggers the requirement for an EPC.
Existing occupiers or tenants will thus not require an EPC unless they sell, assign or sublet their interest.
From 1 October 2008, all buildings that are not dwellings will require an EPC on construction, sale or let.
There are a few exceptions to this rule such as: places of worship, temporary buildings with planned time of use less than two years, stand alone buildings with a total useful floor area of less than 50 square metres that are not dwellings as well as industrial sites, workshops and non-residential agricultural buildings with low energy demand.
EPCs are also not required for buildings due to be demolished.