Display energy certificates (DEC) were introduced in 2008. OGC publish central Government Departments' display energy certificate (DEC) operational ratings on a building by building level twice a year. The most recent data for the Home Office, published on 31 July 2009, which include DEC ratings up to and including 28 February 2009 can be seen via this link:
http://www.ogc.gov.uk/documents/Pan_Govt_DEC_Feb09.xls
This information covers one Home Office Building, 16 UK Border properties and eight Identity and Passport Service buildings.
Data to October 2008 can be seen via this link:
http://www.ogc.gov.uk/documents/Pan_Govt_DEC_Oct08.xls
Data relating to the month ending 30 September 2009 will be published on 18 December 2009.