SAP CalculationsNew Build SAP Assessments

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

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ConversionSAP Assessments

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

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ExtensionSAP Assessments

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

Find out more about Extension

SAP Calculations | EPC's

Vision Energy will work with you on your extension project from design stage all the way through to completion, Vision energy 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.

Extension SAP Calculations & EPC's

When do you need extension SAP Calculations?

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

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 removed 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.




All assessments come with

  • Dedicated energy assessor,
  • Free U-values for Wall, Floor & Roof elements,
  • Commitment to achieve compliance without applying costly or solutions that will prolong the build proccess

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

Building Regulations Part L1b

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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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