SAP calculations for conversions?
Contents |
[edit] Introduction
Calculations carried out using the Standard Assessment Procedure, or SAP, show whether a proposed dwelling meets the energy efficiency requirements of the building regulations. It is primarily used for new-build dwellings, but can be used to assess the performance of extended or refurbished dwellings too.
The SAP methodology was created, and continues to be developed by, the Building Research Establishment (BRE). The government adopted SAP calculations as the preferred approach for assessing the energy performance of dwellings. Major updates to SAP tend to coincide with updates to energy efficiency regulations.
[edit] What do SAP calculations measure?
Measuring the energy performance of a dwelling requires a ‘whole-building’ approach, taking into account a variety of factors and how all of those factors interact. SAP calculations include all of the following:
- Building fabric performance, including U-values of floors, walls, roofs, glazed elements and doors.
- Linear thermal bridging heat losses.
- Heating system and any secondary heating.
- Hot water heating and storage.
- Ventilation.
- Energy efficient lighting.
With the introduction of Part L 2021 in England, the updated SAP 10 features, for the first time, solar photovoltaic systems, detailed information about showers and baths and waste water heat recovery.
Using the SAP methodology, the calculations resulting from the inputted data compare the energy performance of the proposed dwelling with that of a ‘notional’ dwelling of the same shape and size. The proposed emissions must match or better those of the notional dwelling.
In England, SAP is also used to compare the fabric energy efficiency standard (FEES) of the proposed dwelling to the notional dwelling. Again, the regulated energy consumption of the dwelling must match or better that of the notional dwelling.
[edit] When are SAP calculations carried out?
Design stage SAP calculations must be submitted as part of a building regulations application to show that what is being proposed will meet the energy efficiency requirements.
Once work on site is completed, as-built SAP calculations must be submitted to demonstrate that compliance is achieved by what has been constructed. The building control body cannot sign off the dwelling as complete without these calculations.
It is common for the design stage calculations to be carried out only when a more detailed specification starts to be drawn up for the purposes of making the building regulations application. However, there are benefits to having a preliminary calculation carried out in the earlier design stages to help inform planning and layout choices.
Because SAP calculations take into account so many different factors, changing one impacts what is required from all of the others. Setting an outline specification from the outset can help with estimating required external wall thicknesses, or the need to include space for building services, for example.
[edit] Related articles on Designing Buildings
- 2013 changes to the approved documents for part L of the building regulations.
- Air permeability testing.
- Air tightness.
- Applying Fabric First principles: Complying with UK energy efficiency requirements FB 80.
- Approved building energy calculation software.
- Approved documents.
- Building Regulations.
- Building Research Establishment.
- Changes in SAP 10.
- Energy Performance Certificates.
- Energy Performance of Buildings Directive.
- National Calculation Method.
- Passivhaus vs SAP.
- Simplified Building Energy Model.
- Standard Assessment Procedure.
- Target fabric energy efficiency rate.
- U-Value.
Featured articles and news
The 5 elements of seiri, seiton, seiso, seiketsu and shitsuke.
Shading for housing, a design guide
A look back at embedding a new culture of shading.
The Architectural Technology Awards
The AT Awards 2025 are open for entries!
ECA Blueprint for Electrification
The 'mosaic of interconnected challenges' and how to deliver the UK’s Transition to Clean Power.
Grenfell Tower Principal Contractor Award notice
Tower repair and maintenance contractor announced as demolition contractor.
Passivhaus social homes benefit from heat pump service
Sixteen new homes designed and built to achieve Passivhaus constructed in Dumfries & Galloway.
CABE Publishes Results of 2025 Building Control Survey
Concern over lack of understanding of how roles have changed since the introduction of the BSA 2022.
British Architectural Sculpture 1851-1951
A rich heritage of decorative and figurative sculpture. Book review.
A programme to tackle the lack of diversity.
Independent Building Control review panel
Five members of the newly established, Grenfell Tower Inquiry recommended, panel appointed.
Welsh Recharging Electrical Skills Charter progresses
ECA progressing on the ‘asks’ of the Recharging Electrical Skills Charter at the Senedd in Wales.
A brief history from 1890s to 2020s.
CIOB and CORBON combine forces
To elevate professional standards in Nigeria’s construction industry.
Amendment to the GB Energy Bill welcomed by ECA
Move prevents nationally-owned energy company from investing in solar panels produced by modern slavery.
Gregor Harvie argues that AI is state-sanctioned theft of IP.
Experimental AI housing target help for councils
Experimental AI could help councils meet housing targets by digitising records.
BSRIA Occupant Wellbeing survey BOW
Occupant satisfaction and wellbeing tool inc. physical environment, indoor facilities, functionality and accessibility.