The label has a scale of A-G, with A-rated buildings the most energy efficient and G the least.
A BER assessment and certificate may be compulsory to sell a building or shortly after its construction.
BER was created as a tool to help monitoring and improving the overall building energy efficiency.
In Ireland, each new dwelling built from January 1, 2007, required a BER, unless planning application was lodged prior to December 31, 2006.
From January 1, 2009, a BER is required for existing non-residential buildings, when offered for sale or to let.