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SAP CalculationsSAP Assessments & EPCs

Find out how Vision Energy can take care of all your compliance needs for your new Build Project

Find out more about SAP Calculations

Conversion SAP CalculationsSAP Assessments & EPCs

Vision Energy can take care of your energy assessments for your conversion project, find out more today

Find out more about Conversion SAP Calculations

Extension SAP CalculationsSAP Assessments & EPCs

All Extensions with 25% or more glazing compared to the floor area require SAP & EPC assessment and calculations, find out more

Find out more about Extension SAP Calculations

SAP Calculations & Assessments
EPC's For All Building Projects

SAP Calculations in accordance with Building Regulations part L1A (new builds) and part L1B (extensions and conversions). All SAP Calculations are comprehensive and include U-values, Reports for Building Control, and advice and specifications to ensure compliance. We will work with each project from the design stage all the way to completion to ensure the project runs as smooth as possible.

SAP Calculations & EPC Certificates

Vision Energy will work with you on your building project from design stage all the way through to completion, from single dwellings to developments with 100+ dwellings. We strive to ensure that all SAP calculations are completed to achieve compliance as well as providing cost effective and feasible solutions to ensure the smooth delivery of your project. Our expertise and services in SAP calculations span a broad range of building projects including

Our SAP Calculation & Assessment Service

At Visions Energy our SAP assessments include

  • Dedicated energy assessor – This ensures an efficient friendly service. Your dedicated expert energy assessor will get to know you and your project and support you throughout the process.
  • Free U-values for Wall, Floor & Roof elements
  • Commitment to achieve compliance without applying costly options or solutions that will prolong the build process.
  • Fast turnaround available – We are committed to meeting your deadlines and where ever possible we will provide a fast turnaround if this is a requirement.

Elements assessed during SAP calculations

When SAP Calculations are carried out on any dwellings, a number of factors are used to calculate the energy cost & C02 emissions, below is an overview of the elements included within every SAP Calculation:

  • Thermal efficiency of walls, floors & roof elements
  • Thermal efficiency of glazing & doors
  • Boiler efficiency
  • Secondary heating i.e. log burners, open fires
  • Renewable energy i.e. solar panels, Air/ground source heat pumps
  • Air Tightness of the dwelling

How our SAP assessments work throughout the design and build process?

Vision Energy recommend carrying out your SAP calculations at a design stage, however if your dwelling/s is already complete don’t worry, we can still carry out your SAP calculations at an ‘as-built’ stage, below outlines the step by step process Vision Energy will take to ensure compliance to Building Regulations Part L1a & L1B,​

Initial Design Review – Vision will review the plans and information provided within architectural drawings or specifications

Design Stage SAP Calculations – Design calculations will be carried out to review the compliance to all elements in Building Regulations

Design Review & Alterations – Were required, Vision will advise on any alterations that are required to the design of the dwelling/s to comply with Building Regulations Part L1a, ensuring that the design alterations are cost effective and feasible on site,​

Design SAP Calculations & Predicted EPC – Vision will issue the design stage calculations and predicted EPC for submission to Building control/Local Authority​

As-Built SAP Calculations Review – Once the construction of the dwelling/s is nearing completion, Vision Energy will review the construction details compared to the design SAP Calculations to ensure the dwelling/s have been built to the specification, If any alterations have been made, Vision will rerun the calculations and review compliance​

As Built SAP Calculations & EPC – Once the review has been complete and confirmed, Vision Energy will issue and lodge the As-built SAP Calculations & EPC for submission to Building Control/ Local Authority

Vision are more than happy to assist you on all aspects from planning to building control sign off, get in touch to talk to one of our technical team to ensure that your project achieves compliance to Building Regulations part L1A (new builds) and part L1B (extensions and conversions).


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Sustainability & Building Compliance

Vision Energy are a leading Sustainability & Energy consultancy working nationwide. We specialise in calculations & reports covering Building Regulations, Planning Permission and all other sustainability or energy needs within the construction sector. With a vast amount of knowledge and experience having worked on thousands of projects across the UK one of our engineers would be more than happy to assist you on your project. SAP Calculations | SBEM Calculations | Energy Statements | BREEAM Pre-Assessments | M&E Design | EPC's | Water Efficiency | Air Permeability

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New Build SAP Calculations

SAP Calculations & EPCs For New Build Projects

Building Regulations Part L requires all new build dwellings to undergo SAP calculations (standard assessment procedure calculations) to measure the energy efficiency of the dwelling in order to conform to Regulations. 

SAP calculations measure the annual energy costs of a new dwelling, the calculations assess heating elements (including water heating), ventilation, and lighting elements of the dwelling(s). As a result the annual C02 emissions for the dwelling(s) are calculated.

New build SAP Calculation need to be submitted to the appointed Building Control Body (BCB) before any building work commences. The purpose of this is to demonstrated that the proposed development will achieve the required annual carbon emissions targets and minimum thermal performance standards. The SAP Assessment process includes a DER/TER Calculation along with a DFEE/TFEE and DPER & TPER check (applicable to England and Wales only).

On completion of a development, an ‘As Built’ SAP Calculation is provided for each completed dwelling, which is also used to generate an On Construction Energy Performance Certificate.

Read more about our SAP calculations service the process and what is included.

Conversion SAP Calculations

SAP Calculations & EPCs For Conversions

If any property is being converted to a residential dwelling or an existing residential dwelling is being split into multiple dwellings, SAP Calculations will be required to show compliance to Building Regulations Part L1b. SAP Calculations in accordance to Building Regulations Part L1b will assess a multitude of elements of the development from thermal upgrades to the wall/floor & roof partitions, glazing, main heating and much more.

Read more about our SAP calculations service the process and what is included.

Extension SAP Calculations

SAP Calculations & EPCs For Extensions

Vision Energy will work with you on your extension project from design stage all the way through to completion. We strive to ensure that all assessments are completed to achieve compliance as well as providing cost effective and feasible solutions to ensure the smooth delivery of your project.

When do you need extension SAP Calculations?

Building Regulations Part L1b require all extensions with a glazing area that exceeds 25% in comparison to the extension floor area have extension SAP Calculations or heat loss calculations carried out.

So for example:

If your extension is 20m2, you have an ‘allowable’ area of glazing of 5m2 (25% of 20), if your extension does not exceed this figure, heat loss calculations or extension SAP Calculations are not a requirement for Building Regulations. However, if your extension does exceed the 25% figure, SAP calculations or heat loss calculations will be required to show compliance to Building Regulations.

Percentage calculations, points to consider

If you are looking at running calculations to see if you require extension SAP calculations, these are a few things to consider,

  • All openings are considered within the calculations, glazed doors, windows & rooflights, be sure to include these areas.
  • If you are covering or removing any windows/doors in the process of the extension, these areas can be added to the 25%. This can be really useful if you are just over the 25% mark! For example, if you have a 20m2 extension, your ‘allowable’ glazing figure are up to 5m2, however, where the extension is being constructed the external wall previously had french doors which were 2.5m2, these will be removed to make the entrance to the extension. This 2.5m2 of removed glazing can be added to the 25%, therefore your ‘allowable’ glazing area increases from 5m2 to 7.5m2.

Read more about our SAP calculations service the process and what is included.

Building Regulations and SAP Calculations

SAP Calculations been a requirement in the UK since 1995 under Part L of the Building Regulations. These calculations are necessary to produce a Predicted Energy Assessment and an Energy Performance Certificate (EPC certificate). Building Regulations require that a SAP calculation and a predicted EPC is submitted for new dwellings prior to the commencement of work.

SAP calculations are important to demonstrate compliance with Part L and also to produce an EPC. They are also also used to determine a SAP score/rating for the property. The SAP score, between 1 and 100+, estimates the annual energy related running costs of a dwelling. A higher the rating, indicates lower energy usage & running costs, with 100 representing zero energy cost. A SAP score over 100 indicates a net exporter of energy. Therefore, the higher the SAP score, the lower the fuel costs and the lower the associated emissions of Carbon Dioxide (CO2).

Building Regulations Part L1a

Building Regulations Part L1b

Building Regulations Part L (2021)

What is the target a dwelling needs to meet?

When it comes to achieving compliance, no set standard is in place that a dwelling needs to meet. During the SAP calculations (standards assessment procedure calculations) the target will be calculated based on a number of factors such as dwelling size, orientation, design & layout. Therefore each dwelling has a completely unique target to achieve, Based on the target being unique to each dwelling Vision Energy recommends completing your SAP calculations at a design stage. For a conversion project targets can be found within Approved Document Part L1b, or alternatively, give one of our technical advisers a call. 

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Frequently Asked Questions

Get your SAP calculation completed at the design stage this give time for alterations. Utilise good building fabric and also consider ways to lower the thermal mass to reduce the energy require to heat the building fabric. Use renewables where possible such as waste water heat recovery or photovoltaic panels. Avoid heat escaping between dwelling by in insulating party walls.  Use the latest technology in smart heating controls and low energy light bulbs.

To read more visit our blog post:  How to pass SAP Calculations

SAP Calculations are carried out by a qualified On-Construction Domestic Energy Assessor. The assessor should hold the relevant certification and insurance to cover the SAP Calculations work. If you have any queries on qualifications or insurance, please contact our team and we will be able to provide all relevant documentation.

SAP Calculations are the calculations behind the production of an EPC for a new build, change of use, or extended dwelling. The calculations will show compliance to Building Regulations Part L and also produce the relevant figures to assign a rating of 1-100 to the dwelling, showing how energy efficient the dwelling is, also known as the EPC (energy performance certificate).

SAP standards for Standard Assessment Procedure. This procedure is an approved method of calculating and assessing the energy performance of a dwelling.

It is recommended to carry out SAP Calculations at the design stage of your project initially, this is to review compliance for all elements of the build, in accordance with Building Regulations Part L. This allows for any amendments to be made prior to the build starting on site.

If your project has already commenced and SAP Calculations have not been completed, SAP Calculations can still be produced at this stage, we would just work with ‘as-built’ information rather than ‘as designed’.

On completion of the project, the SAP Calculations will be updated and an EPC produced.

The cost of SAP Calculations can vary depending on dwelling numbers, size, and complexity. Single dwelling SAP Calculations normally start at £245+VAT