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SAP Calculations & EPCs


SAP Calculations are an energy efficiency calculation, required by the Building Regulations on all new build properties, and some converted properties and extensions

SAP stands for Standard Assessment Procedure. A SAP rating is given on a calculation – this is a figure between 1 and 100+. A figure of 1 would represent an extremely un-efficient home, 100 would be a dwelling with zero energy cost, and anything over 100 would mean you are able to export energy.

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Since 2008, in response to the Energy Performance of Buildings Directive (EPBD), all new homes in the United Kingdom under construction require a Predicted Energy Assessment (PEA) and an On Construction Energy Performance Certificate (OCEPC).

SAPs are used in partnership with the PEA during a property’s design phase. This is done to attain Building Control approval for the property; a legal requirement in the UK, according to Part L1a of Building Regulations (as with Air Tightness Testing.)

RJ Acoustics work with experienced assessors and experts whose SAP calculations come with a pass guarantee based on their recommendations.

Contact us today for more information on how to get the required calculations and consultancy for your property, to attain Building Control approval and an EPC.

What is a SAP Calculation?

The SAP Calculations establish an energy cost based on the construction of the home, its heating system, internal lighting and any renewable technologies installed.

A SAP Calculation is used to determine the Carbon Index and ‘energy values’ for new homes. SAPs also apply to dwellings and developments that are created by conversions or ‘material changes of use.’ SAP Calculations, carried out by an assessor, help to provide the EPC Rating for a property. The EPC, takes a variety of factors into account including:

  • The architect’s plans and drawings
  • Construction details and information (such as build materials)
  • Heating, ventilation and insulation for the property

Part L1a Building Regulations

Part L1a of Building Regulations (read the full document here) has been part of UK law since April 2014 and pertains to new buildings and some property extensions. It requires all qualifying builds and extensions to adhere to a number of requirements to conserve fuel and power, ensuring buildings are more energy efficient throughout the UK.

New-build SAP/EPC legislation states that an OCEPC is valid for 3 years.

Do I Need a SAP Assessment?

All new build dwellings require a SAP assessment. If your project is a barn conversion, a single dwelling into flats or a change of use it is likely that Building Control will ask for Part L1b SAP Calculations. If your project is an extension, and the glazing on the extension covers more than 25% of the extension area, you will likely need a SAP Calculation. It is crucial to check whether your extension requires these calculations, in order to comply with Approved Document L.

SAPs tell the assessor and Building Control a number of important points about the property:

  • Whether or not the building exceeds Carbon Emission Targets
  • The performance of the property with regards to its energy use
  • The Energy Efficiency Rating of the property

Contact Us Today for SAP Calculations and EPCs

We offer the highest levels of service and expertise and are always happy to work with our customers to give you the best possible chance of achieving a pass on your SAP Calculations and EPC.