Compliance with articles 3, 4 ,5 and 6 of the EPBD in England and Wales has been achieved through Building Regulations that came into force on 6 April 2006. These introduce a National Calculation Methodology, as required by the Directive. For housing, the calculation will be a new version of the existing Standard Assessment Procedure SAP, so the procedure will not be too different from the present situation. For non-domestic buildings (and a few large dwellings), new procedures will be used. The simplest of these is the Simplified Building Energy Model SBEM.