Communities and Local Government
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- Planning, building and the environment
- The Environment
- Energy Performance of Buildings
- Energy Assessment Process
Energy Assessment Process
All energy certificates should be produced using the relevant calculation tool specified in the National Calculation Methodology. This applies for all Energy Certificates whether on construction, sale or rent, or for public display.
This section provides an overview of the assessment methodologies and where they should be applied
Assessment methodologies
A number of different methodologies have been developed (or are in the process of being developed) for different types of building and building condition. A summary is provided below:
| Condition requiring a Energy Performance Certificate | Assessment Methodology |
| A dwelling on completion of construction | SAP |
| Building not intended as a dwelling on completion of construction | SBEM or DSM |
| A dwelling being sold or rented out |
RDSAP (unless the unusual nature of the building indicates that a more accurate assessment could be obtained using the SAP methodology) |
| A building catering for mixed use (i.e. combining dwelling and non-dwelling) is constructed, sold or rented out |
It should be treated as a single dwelling as described above if the commercial part can be coverted back to residential use and there is common access i.e. each part does not have a seperate access(for example, where within a house a portion has been separated out as a workshop, office, or surgery); For other scenarios, treat the dwelling and non-dwelling parts seperatley using the most appropriate methodology for each element. For example, where a building contains both flats and offices use SAP or RDSAP for the flat and SBEM or DSM for the offices. |
| For all other buildings being constructed, sold or rented out | SBEM or DSM |
| When a Display Certificate is required for public display | Operational Rating Methodology |
The methodologies explained
SAP - Standard Assessment Procedure
SAP is the Government's Standard Assessment Procedure for energy assessments of dwellings. The current version of SAP, SAP 2005, has been adopted by Government as part of the England and Wales national methodology for calculation of the energy performance of buildings. It is used to demonstrate compliance for dwellings with Part L of the Building Regulations 2000 (in England and Wales). For further information visit: www.projects.bre.co.uk/sap2005/ [External link].
SBEM - Simplified Building Energy Model
SBEM is a computer program developed by BRE that provides an analysis of a building's energy consumption. The SBEM tool is designed to cover buildings that are not dwellings. It has been adopted by government as part of the UK national methodology for calculation of the energy performance of buildings. It is used to demonstrate compliance for dwellings with Part L of the Building Regulations 2000 (in England and Wales) For more information visit: www.ncm.bre.co.uk/ [External link].
Operational Rating Methodology
The methodology for the calculation of the operational ratings for display energy certificates is currently being finalised.
RdSAP - Reduced Data Standard Assessment Procedure
RdSAP is the new Government-approved standardised assessment procedure for energy assesments of existing dwelling. A full SAP assessment requires many data items that cannot be seen in a survey (or take too long to collect). RdSAP is an industry-agreed standard set of data items and a standard way of inferring the missing data. For more information visit: www.nher.co.uk/pages/insight/rdsap.php [External link] or www.rdsap.info [External link].
DSM - Dynamic Simulation Model
A Dynamic Simulation Model is a software tool that models energy inputs and outputs for different types of building over time. In certain situations, SBEM, will not be sophisticated enough to provide an accurate assessment of a building's energy efficiency. In these cases Government-approved proprietary dynamic simulation models may be used. Communities and Local Government will provide such an approval.
