Advisory Reports (AR) provide information about the way energy is managed and used within a building.  They provide recommendations for improving energy efficiency which can help reduce energy bills if successfully implemented.  Even where they are not required, it is often beneficial to have the AR for a building completed or updated.  This is particularly true when the energy assessor has to complete a site visit to issue the DEC as the additional work for the assessor is limited and this should be reflected in the assessment price.

In England & Wales, a valid Advisory Report is legally required to be in place before a DEC is issued.  In reality, they are usually both added to the national register at the same time when required but they can be completed separately.  The Advisory Report must be for the same building and occupier as the DEC so they should both be accessible under the same entry on the register.  It is the responsibility of the energy assessor to check the register to ensure that the AR is in place before lodging the DEC.

In Scotland, Advisory Reports are voluntary but will be required if it is intended to use the DEC within the Energy Saving Opportunities Scheme (ESOS).