1.1 A new building must be built to a minimum standard of total energy performance. This is evaluated by comparing calculations of the performance of the ‘actual building’ against calculations of the performance of a theoretical building, called the ‘notional building’. This must be carried out both at the design stage and when work is complete.
The notional building is the same size and shape as the actual building and has standardised properties for fabric and services. The full properties of the notional building are set out in the National Calculation Methodology Modelling Guide, which is available from https://www.uk-ncm. org.uk/.
1.2 The energy performance of the notional building is described using the following metrics.
a. The target primary energy rate, in kWhPE/m2 per year.
b. The target emission rate, in kgCO2/m2 per year.
1.3 The target primary energy rate and target emission rate must be calculated using one of the calculation tools in the approved methodology, used in line with the version policy as stated in the methodology. As part of the submission to the building control body, the applicant should show that the software tool used is appropriate to the application. The calculation tool can be either of the following.
a. The Simplified Building Energy Model (SBEM), for buildings with design features that are capable of being adequately modelled by the Simplified Building Energy Model.
b. Other software tools approved under the Notice of Approval.
NOTE: An up-to-date list of approved software can be found on the Department for Levelling Up, Housing and Communities webpages.
NOTE: Information on the approved methodology, the version policy for these tools and how to choose an appropriate modelling tool can be found in the National Calculation Methodology Modelling Guide.
