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Sap Calculations

Do you need SAP calculations for your project? We’ll work with you to ensure your property is compliant with the building regulations. All at an affordable price. Contact Energy Smart today.

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Sap Calculations, Just What Are They?

Have building control or your architect asked you to get sap calculations. Why do you need them and just what are sap calculations anyway? Then read on.

SAP is short for Standard Assessment Procedure and its the UK government’s method of calculating the energy efficiency of dwellings. The calculations are needed to show that a building conforms with specific energy targets laid down in the building regs.

In a simple summary, that’s more or less it. 

Sap Assesments are usually required for 3 main reasons

  • For all newly built homes.
  • For a dwelling change of use, for example changing a commercial building to residential flats.
  • For overglazed extensions. 

The two main areas which the sap calculations will be looking at is that the carbon emissions from your property are within set tolerances and that particular components of the property, such as the windows, walls , roof, and floors comply with specified thermal targets.

A good set of construction drawings must be provided to the Assessor, because all the calculations are done from the building drawings ,so there is no need to visit the property. Your Assessor will advise you of precisely what is needed.
Once the calculations are done, an Energy Performance Certificate or EPC can also be created.

If your sap calculations show that your property isn’t compliant, then your Assessor will give you advice on improvements which can be made to make it so.

It is important to liaise with your Assessor as early on in the project as possible because once the building is finished any non-compliances could possibly be quite costly to rectify.

Should you need advice on a project you could have in or around your area, or simply require a quotation, contact us or fill in our get a quotation form.

We’re here to help.

Sap Assessor

Want an answer to a question you might have about SAP calculations in the UK? The following are the 10 most typical questions.

What Are As Built SAP Calculations
These are the finished set of SAP calculations produced once the dwelling has been completed to hopefully demonstrate that it is compliant with Part L1A of the building regulations. Ahead of the building starting, it ought to have had a set of “Design Sap” calculations to demonstrate that the proposed dwelling, on paper at least, would be compliant with Part L1A.



Sap Calculations, Just What Are They?
This is by far the most frequent query asked. Have a look at Andrea’s video explanation above, or read the full explanation here on the right.
Sap Calculations, How Much Do They Cost
We would be pleased to provide discount rates, especially for multiple dwellings which are the exact same or very similar design. But typically for a single dwelling the price would be in the region of £120 – £300. By providing the plans, it will be possible to get yourself a fixed price quotation.
How To Do Sap Calculations
Unfortunately this is not some thing that can be done yourself. Sap calculations must be carried out by an On Construction Domestic Energy Assessor or OCDEA, using approved Government software. The Assessor needs to be approved under one of the certification schemes and is regularly audited to keep their accreditation.
What Information is Needed For A Sap Assessment
Your Assessor would advise you of exactly what is needed. Typically you would need the following:

  • Floor Plans to include sections and elevations
  • Orientation of the property
  • Construction specification of walls, roof and floors
  • Specification for all doors and windows
  • Primary and secondary heating
  • Provision for providing  hot water
  • Any renewable technology (if any)


Sap Assessment For New Build
Every new dwelling require Sap calculations to prove compliance with Part L1A (Conservation of fuel and power in new dwellings) of the building regs.
Sap Calculations For Extensions
It’s now quite popular to have large bi-folding doors, sky lights and large quantities of glazing on new extensions. But with the present building regulations the amount of glazing can be no more than 25% of the floor area of the new extension. So over compensations on the thermal elements in other areas of the property will need to be made to demonstrate that the CO2 emissions from the current house and the proposed extension is not any worse when compared to the existing house and an extension where the glazing is within the allowed amount judged against Part L1B of the building regulations.

You will need SAP calculations to find solutions and demonstrate compliance.


Sap Calculations For Conversions
For anybody who is changing the use of a dwelling, you will need Sap calculations. {The new dwelling will have to comply with Part L1B of the building regulations.}


Do I Need Sap Calculations
p>You will need Sap calculations for any of the following: 

  • Building a new property
  • Changing the use of an existing property (e.g, a barn conversion, commercial building to residential)
  • Extensions with more than 25% glazing
  • Opening up the main house to an existing conservatory
  • Extension where the extension is more than 50% of the original property wall area
  • Garage conversions
  • If requested by building control

This is not an exhaustive list. Give us a call, if you are not sure if you need them.


Our Services


SAP For Dwelling Change Of Use

  • Reports for Part L1B Compliance
  • Free Advice

SAP For Overglazed Extensions

  • Carbon Emissions Reports
  • Heat Loss Calculations
  • Free Advice

SAP For New Builds

  • Reports for Part L1A compliance
  • Free Advice
We also cover the whole of the UK 

What You Can Expect From Us

Trusted & Experienced

Our Assessors are fully qualified and accredited with several years experience carrying Sap calculation in the UK . We also cover the whole of the UK and can help on any project nationwide.

Reliable & Fully Insured

You will be allocated a dedicated Assessor who is also covered by full professional indemnity insurance up to £100,000 so that you know you’re in save hands.

Prompt Service

We’ll respond to your enquiry within 24 hours. We’ll also help you to deliver your project within your timescale.

Satisfaction Guaranteed

We aim to provide 100% customer satisfaction and look forward to working with you.


Get A Quote, Or Call Us For Advice