Standard Assessment Procedure, or ‘SAP calculations’ as they are commonly referred, is the methodology used by the Government to assess and compare the energy and environmental performance of dwellings.

Its purpose is to provide accurate and reliable assessments of dwelling energy performances that are needed to underpin energy and environmental policy initiatives.

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Upon completion, A ‘SAP rating’ is given. This is the calculation that is required in order to produce a Predicted Energy Assessment and an ‘On Construction Energy Performance Certificate’ (EPC).

Building Regulations require that a SAP calculation and a Predicted EPC is submitted for new dwellings prior to the commencement of work.

A SAP calculation indicates a score from 1 to 100+ for the annual energy cost based on:

  • The elements of structure
  • The heating and hot water system
  • The internal lighting
  • The renewable technologies used in the home.
  • The higher the score the lower the running costs, with 100 representing zero energy cost. Dwellings with a rating in excess of 100 are net exporters of energy.

This blog sets out to explain some of the key information needed from the building owner, contractor or person in charge of organising the SAP calculation.

SAP Calculations Are A Desktop Exercise

SAP calculations are produced using a computer model.  As a desktop exercise, there is no need for the SAP Assessor to conduct a site survey. With that in mind, it is important to provide as much information as possible.

An inaccurate assessment will inevitably slow down productivity, costing time and money in the long run.

Information Needed For A SAP Calculation

Specific information will vary from project to project (and your SAP assessor will inform you of this), but below is a typical list that is usually required.

  • The full building address.
  • The correct postcode as confirmed by Royal Mail.
  • Elevations drawings for each elevation.
  • Details of the principal heating and hot water system. This needs to include the make and model of boiler, details of heating emitters (e.g. radiators), hot water cylinder size (if applicable) and the system controls.
  • A site plan, including the orientation of the dwelling(s).
  • Scaled plans of each storey of the building (normally at 1:100).
  • Sectional drawings of the dwelling.
  • Details of any secondary heating system present.
  • Details of ventilation systems or extractor fans.
  • Details of the internal and external lighting.
  • Details of any renewable technologies installed in the building.  These could include ground source heat pumps, air source heat pumps, solar water heating, photovoltaics (PV), wind turbines and/or hydrokinetic technologies.
  • Details of the construction of all the different external walls to the property.  This needs to include the type and thicknesses of insulation and other building products used.
  • Details of all the doors and windows.  This needs to include the sizes, type of frame, type of glazing, thickness of glazing and any low emissivity applications.
  • Details of the construction of all the different roofs to the property.  This needs to include the type and thicknesses of insulation and other building products used.
  • Details of the construction of all the different floors to the property.  This needs to include the type and thicknesses of insulation and any other building products used.

If you are in the process of designing the building, the SAP assessor can help you decide upon the minimum standards for each system to ensure the finished building meets the required performance energy standards.


As previously stated, the level of information will vary from project to project, but this is a high-level overview of what’s generally required in order to efficiently carry out a SAP calculation.

We hope you found this post useful. If you would like to find out more about our SAP calculation services or would like to speak to one of our team members about energy advice for your property, get in touch on 01372 438 039 or fill out the form below and we’d be more than happy to help.

Have you read any of our other blogs on SAP calculations? Click the links below:

SAP calculations ebook | Sustain quality

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About Us

We are a friendly team of Engineers delivering Sustainability and Building Compliance Solutions for developments in the Commercial and Residential sectors, which include Energy Statements, Noise Impact and Vibration Assessments, BREEAM Assessments, and Air Quality Assessments in the Environmental, Social and Governance sectors.

Contact us at:

Sustain Quality Ltd

PO Box 393


KT11 3EL

01372 438039