Book in your SAP calculation now. We aim to complete your SAP in a 48 hour time period.

Email us at -



    SAP Calculations or “standard assessment procedures” are a mandatory building regulation requirement. The Government has made SAP calculations to calculate the energy performance of domestic dwellings. SAP calculations need to be conducted on all new residential developments, extensions and conversions and a score on a scale between 1 – 100 will be issued after the calculation has taken place. 

    If a lower score is issued this will indicate a higher energy running cost for the dwelling being tested.  The fundamental reason SAP calculations are conducted on new build developments is to calculate how to design the most efficient building.  


    When are SAP Calculations needed?

    SAP calculations should be carried out before building work even begins. This procedure is carried out, so that at the design stage you can be assured that the plans will achieve a pass. It’s worth nothing, that in the case of L1A SAP calculations, there is a second report required once the building work has been completed.


    SAP calculations are completed in two separate ways (L1A and L1B). If you are in the process of developing a domestic new build dwelling, conversion or extension you will more than likely require a SAP to complete your EPC (Energy Performance Certificate) and sign off the building regulations.

    L1A SAP calculations are performed for all new build developments, whereas the L1B SAP calculations are specifically aimed at extensions and conversions.

    In order to sign off building regulations an EPC certificate must be issued. One main component that makes up the EPC is a SAP calculation. As the focus on the conservation of fuel and power has increased over the years, the government made it a legal requirement in 1995 that an EPC must be issued before renting or selling a property in the UK.

    How can we help?

    We have been carrying out SAP calculations for a long time – whether it’s customers who are designing new builds, extensions or conversions. We are here to ensure you move quickly and painlessly through the process.

    Our experienced energy assessors can guarantee we will carry out all the necessary work to ensure your project passes the building regulations. We take on every job with the goal of completing the work in the quickest time possible, while maintaining the unrivalled quality assurance of Purple Energy.

    Please don’t hesitate to contact us. We are always happy to help.

    sap calculations

    Factors that determine
    Standard Assessment Procedure

    A number of factors are taken into account when calculating a SAP. These will have an impact on the final score you achieve. Some of these are:

    • Ventilation Test and Air Tightness Testing results.

    • Type of building materials and thermal insulation used to construct the dwelling. 

    • Instalment of renewable energy technologies e.g. thermal heat pump, solar panels.

    • Productivity and governance of the buildings heating system.

    • Method of heating water and preference of space, ventilation and lighting. 

    • Solar Gains.

    • Productivity and control of heating system.

    Passing the
    SAP assessment

    Successfully reaching the score you need to pass your SAP calculation is reliant on a set of components which our experienced SAP assessors have multiple years of experience dealing in. Our aim is to guide you through building compliance with as little stress as possible.

    Don’t hesitate to get in touch with one of our dedicated team members now.

    Get a Quote

    If there is anything you feel unclear about or you simply want to speak to one of our team members, don’t hesitate to give our office a call.

    Email us at

    Call us on

    Contact Us

      Frequently Asked Questions

      To make things easier for you guys, we have a couple of common questions that we receive from clients.

      SAP stands for ‘Standard Assessment Procedure’ and is the method used by the government for calculating the energy performance of dwellings.

      As we stated above, SAP ratings are calculated as “The Government’s Standard Assessment Procedure for Energy Rating of Dwellings”. Although, in fact, the score is based on the energy costs. The scoring system is expressed on a scale of 1-100, which breaks down as the higher the number the lower the running costs. 

      The short answer is no, but in some cases yes. Not all extensions will need a SAP calculation. According to the regulatory building standards, as long as any areas of new glazing account for no more than 25% of the new floor area (plus an allowance for existing windows that need to be removed) then an additional SAP calculation isn’t required. 

      In recent years many building works have been carried out with the purpose of creating fresh, light and airy spaces. For some of these types of constructions, the 25% allowance will be exceeded and there will be an additional SAP calculation required. 

      This is largely dependent on the timeline of your construction project and those that are working on the project. Though working within standard UKBC times, the reports are completed within 5-10 working days after request.