The Energy Performance Certificate (EPC) is broadly similar to the certificates found on many domestic appliances. A Certificate for a building gives the building an asset rating based on its energy efficiency, but doesn't take into account how the home is used by the occupiers.

The Certificate will give the building a rating from A to G. An A rating shows it's very efficient, meaning lower fuel bills, while G is inefficient, meaning higher fuel bills. The Certificate will also show the building's environmental impact by indicating its carbon-dioxide emissions.

What does an assessment for an EPC involve?

An accredited energy assessor needs to visit a property to conduct an energy assessment for an existing building. During the assessment they collect information on the property, which includes details of its dimensions, construction and heating/hot water provision. The time taken to perform an energy assessment will vary according to the size and nature of the property. Because of the wide variation of commercial buildings, any form of 'average time' would not be meaningful. This information is fed into the approved software programme which produces the EPC and recommendation report. The energy assessor will then record the certificate onto a national register via his or her accreditation scheme (http://www.spsc.lt)  and provide the seller, or prospective landlord with a copy. The certificate is then ready to be given to new building owners or made available to prospective buyers or tenants.

Which buildings don’t need an EPC

The following buildings don’t need an EPC when they are built, rented or sold:

• places of worship
• temporary buildings that will be used for less than two years
• standalone buildings with total useful floor area of less than 50 metres squared that aren’t used to provide living accommodation for a single household
• industrial sites, workshops and non-residential agricultural buildings that don't use a lot of energy