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  • New Dwellings
    SAP New Dwellings

SAP Calculations / New Dwellings

Building Regulations require a SAP Calculation for every new dwelling. The SAP Calculation needs to be given to your Building Control Provider (Approved Inspector or Local Authority Building Control) before work starts on site.

Once a dwelling is complete the SAP Calculation is used to produce an Energy Performance Certificate. We pride ourselves in delivering a personal service with a commitment to clear and cost effective advice.

Here are some points to consider before making a choice of SAP Assessor:

  • We provide a full consultation service as standard – all the advice and support you need to ensure you meet the required level of performance.
  • Design Stage and As Built Calculations as well as Energy Performance Certificates are included in our standard service – there are no hidden extras!
  • Calculations are carried out by accredited and experienced construction professionals – providing cost effective and practical solutions.
  • We have a track record of providing advice to clients that saves thousands of pounds - you can be sure we’re providing solutions that work for you.

Call now to get a quote or discuss your project with one of our SAP Assessors.

Why is SAP Calculation needed?

The requirements of Building Regulations Approved Document L1A mean that a SAP Calculation needs to be carried out for every new dwelling. The SAP assessment calculates the energy efficiency of a dwelling and is used to demonstrate compliance with Building Regulations.

Since October 2010 it has been mandatory to submit initial SAP Calculations to your Building Control Provider (Approved Inspector or Local Authority Building Control) before you start on site.

Whether the property is newly built, or created by the conversion of an existing structure, an Energy Performance Certificate is also required; these Certificates are produced using the SAP Calculations and can only be provided by accredited Energy Assessors.

How do you know the SAP has passed?

Building Regulations now place greater emphasis on the quality of the building fabric, efficient heating systems with better controls, renewable technology, solar gain and controlled ventilation.

These factors combined with the fuel used to heat and light the property enables a Dwelling Emission Rate (DER) to be calculated. This is then compared with the Target Emission Rate (TER) based on a notional building of the same size and built form. To comply with Building Regulations the DER must be lower than the TER.

In addition certain limiting factors need to be met; there are minimum levels of performance for the thermal envelope (U-Values) and air permeability as well as efficiency of heating systems and their controls.

If your project fails the initial SAP Calculation we will provide guidance and support free of charge outlining the most cost effective ways of amending your specification in order to achieve a pass.

Why choose us to complete your SAP Calculations?

Our Energy Assessors undertake the SAP Calculations from the plans and specifications you provide. We have also developed a simple checklist so you understand exactly what information we require. These factors ensure we can provide you with full SAP calculations within 3-5 days of receiving the information. All customers benefit from a full consultation service to ensure you achieve the performance levels you need for either Building Regulations or Code for Sustainable Homes.

Because our Energy Assessors are dealing with a range of customers, from large developers to individual self-builders, we have a constantly expanding knowledge of the latest technologies and innovations. This knowledge is passed on to our customers, ensuring that you have access to the best advice and can achieve the desired results while keeping costs to a minimum.

Our quoted prices for SAP Calculations include the production of the Energy Performance Certificates; required by the EU Energy Performance of Buildings Directive. Some SAP Assessors will only include the cost of the SAP Calculation in their quotation and may charge an extra £25 (or more) per unit for producing Energy Performance Certificates. Our quotes also include the provision of a Predicted Energy Assessment (PEA) were required by the client.

If you place an order for Code for Sustainable Homes and SAP calculations with us at the same time you will benefit from a 10% reduction on the cost of both.

How can I improve SAP performance?

The SAP Calculation measures the energy performance of a new dwelling – how efficiently it is heated and lighted. Retaining heat and generating it efficiently uses less fuel; less fuel means less emissions and a better result in the SAP Calculation. There are many factors that can affect the result but by focusing on the following it is possible to achieve a pass while minimising additional cost.

  1. Improved insulation

    The more and better your levels of insulation the better your SAP Calculation result will be; simply bettering Building Regulations U-values isn’t enough. Choosing higher grade products may be more expensive but can be offset by not having to specify things such as renewable technology which can add to build costs.

  2. Higher performing windows

    Glazing has a big effect in the SAP Calculation. Windows can be a substantial heat loss element so lower U-values will help improve the result. Make sure suppliers give you the U-value for the whole unit – including the glass and frame.

  3. Accredited Construction details

    Thermal bridges are areas where the insulating layer is penetrated by a more conductive material and therefore form another source of heat loss. Examples of thermal bridges include around window and door openings as well as roof / wall junctions.

    Adopting Enhanced and / or Accredited construction details will limit the thermal bridges and can have a significant benefit in the SAP Calculation. For more information visit the Energy Saving Trust and CLG websites:-

  4. Use 100% low energy lights

    Building regulations require 75% of light fittings in new dwellings to be dedicated low energy. If you increase this to 100% it can offer a simple and effective way to improve your SAP performance. Note that low voltage halogen spotlights are not counted as low energy fittings.

  5. Fully fill and edge seal party walls

    Party walls are now deemed to contribute to heat losses so a straight forward benefit can be gained by sealing the edges and filling the cavity of party or separating walls between dwellings.

    Be sure to pay attention to Building Regulations Part E requirements for sound transmission.

  6. Improve air tightness

    Every new dwelling must limit air permeability with a Building Regulation maximum value of 10m3/ through the envelope. Setting a target lower than this will help in SAP Calculations as it will further limit heat loss and the need for heating (and therefore emissions). Make sure the target is realistically achievable and ensure any background ventilation is appropriate for the level of air tightness you specify.

    Also be aware that on sites of more than one dwelling if you only test a sample number of units those that are not tested will be subject to an additional “confidence factor” (the average result of the tested dwellings +2). This can mean the testing of more dwellings than required under Building Regulations is a cost effective route to improving overall performance in the SAP Calculation.

  7. Renewable & Efficient Technology

    A range of technologies are available to help a dwelling lower its emissions and improve its performance in the SAP Calculations. At the cheaper end consider high efficiency boilers and high specification heating controls (such as full Time and Temperature Zone Control, Weather Compensation, etc.). You may also want to consider Flue Gas Heat Recovery devices, Solar Hot Water Panels, Solar Photovoltaic Panels, Ground Source Heat Pumps or Air source Heat Pumps.

What do I need to provide to the SAP Assessor?
  • Floor plans, building elevation and section drawings;
  • Details of the buildings location and orientation;
  • Specification for the construction of all floors, roofs and external walls;
  • Specification for all windows and doors within the buildings external envelope, including frame material, width of gap (if multiple glazing) and emissivity of glass;
  • Details of the primary heating system (such as the make and model of the boiler) and associated controls;
  • Details of the hot water system, including cylinder size, details of any insulation to the cylinder and pipes, and associated controls;
  • Details of any fixed secondary heating (such as a wood burning stove);
  • Details of any mechanical extract or ventilation systems (for example, the number of mechanical extract fans);
  • The number of standard light bulbs and the number of low energy light bulbs; and
  • Details of any renewable technology, such as solar hot water or photovoltaics.
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Contact us

PB Sustainability Ltd.

Office 64
The Old School
Wallasey, Wirral
CH44 5TN