National Calculation Methodologies

Building Regulation 17A requires the Secretary of State to approve a national calculation methodology (NCM). This has been effected by the Notice of Approval of the Methodology of Calculation of the Energy Performance of Buildings in England and Wales.

The notice of approval sets out:

a) The methodology of calculation of the energy performance of buildings including methods for calculating the asset rating and operational rating of buildings; and
b) The ways of expressing the energy performance of buildings as calculated in accordance with the methodologythat are approved by the Secretary of State for the purposes of regulation 17A of the Building Regulations 2000 as amended.

The approved methodology comprises the following calculation methods:

a) The Standard Assessment Procedure for the Energy Rating of Dwellings (SAP 2005);
b) Approved software applications of SAP 2005 as indicated in the notice;
c) The Government’s Simplified Building Energy Model (SBEM);
d) Approved software interfaces to SBEM as indicated in the notice; and
e) Approved Dynamic Simulation Model (DSM) software packages as indicated in the notice.

Details of how to apply for approval of software can be found in the document Criteria for Accessing Software for Approval for Use in Building Regulations Energy Performance Calculations.