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What Are Sap Calculations

Have building control, or perhaps your architect asked you to get sap computations. Why do you need them and what exactly are sap calculations anyway? Then continue reading.

You can either click on the video clip on this page, where Andreas will shed some light on this, or read on.



Ealing SAP Calcs For Dwelling Change Of Use

  • Reports for Part L1B Compliance
  • Free Advice

Ealing SAP Calcs For Overglazed Extensions

  • Carbon Emissions Reports
  • Heat Loss Calculations
  • Free Advice

Ealing SAP Calcs For New Builds

  • Reports for Part L1A compliance
  • Free Advice

What does SAP mean?

SAP is short for Standard Assessment Procedure and it is the united kingdom government’s means of determining the energy performance of properties. These calculations are needed to prove that a building conforms with certain energy targets set down within the building regs.

That’s basically it in a simple overview.


When Are SAP Calculations Needed?

Sap calculations usually are required for 3 reasons

1. For all new dwellings
2. For a dwelling that’s changed its use,e.g converting a commercial building to residential flats.
3. For extensions that have over 20% glazing

The sap calculations are required to establish that the dwelling emission rate (DER) and the dwelling fabric energy efficiency (DFEE) conform to certain targets.

The computations are carried out by a certified and accredited On Construction Domestic Energy Assessoror OCDEA for short. There is no need to visit the property because all the computations are carried out from the building drawings ,so a good set of plans are very important. When the calculations are completed, an Energy Performance Certificate or EPC can also be produced.

Your Assessor can provide you with further advice in the event the calculations show that your building isn’t compliant, as well as let you know which is the best changes to make. It’s very important to liaise with your Assessor as early on in your project as possible because once the building is completed any non-compliances might be quite costly to rectify.

Should you require guidance on a project you could have in , or simply require a quote, give us a call or fill in our get a quotation form.


SAP Calculations in Ealing The 10 Most Common Questions Asked.

What Are Sap Calculations

This really is by far the most common question asked. Check out Andrea’s video explanation above, or read the full explanation here on the right.

How Much Do Sap Calculations Cost

The average price range can be between £100 – £300, this can be depending upon the complexity and size of your property. Should you also require an Energy Performance Certificate (EPC) at the end of it there may be an additional charge of about £50 to register the EPC on the register. For a number of dwellings of comparable types, then discounts could well be available.

What’s The Difference Between Sap and EPC

Before we get to the differences, this is what you will require depending on your project.

For a new build property you’ll need – SAP calculations and an EPC.

For dwelling change of use or conversion you’ll need – Sap Calculations and an EPC.

For overglazing on an existing dwelling you’ll – Sap calculations only.

SAP or Standard Assessment Procedure are the computations of pre defined data set of a buildings design that’s created to display the energy effectiveness of a property. EPC stands for Energy Performance Certificate and it’s a summary report of the SAP calculations in an simple to grasp report, which could also be used to market or rent out a property.

There are actually two types of EPCs. The first is a SAP EPC that is produced from building plans where all the elements of the building are known. This would normally be needed by building control to demonstrate that the property meets certain targets essential to the building regulations. Building control would also need to see the SAP calculations which shows in greater detail whether all of the elements going into your property conform to the building regulations.

The second variety of EPC is the common one that would be required when you are selling, or renting out a property. This particular EPC uses what’s called rdSAP, which stands for Reduced Data Standard Assessment Procedure, and is used where certain thermal values of, such as, the walls, roof, floors, etc, are not precisely known on an established property. In this situation assumed thermal values are used based on the age of your property. This particular EPC would be no use to demonstrate compliance with any building regulations. Sometimes building control would simply ask you for an EPC, but what they would really require are the Sap calculations (which is the information behind the EPC) and the SAP EPC (which is actually summary report of the Sap calculations).

If you are still confused, then call us for further information.

What Are As Built SAP Calculations

These are the final 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 some “Design Sap” calculations to demonstrate that the proposed dwelling, in theory at least, would be compliant with Part L1A.



Can I Do The Sap Calculation Myself

Unfortunately this is not some thing you can do yourself. The calculations have to be carried out by an On Construction Domestic Energy Assessor or OCDEA, using approved Government program. The Assessor must be approved under one of the accreditation schemes and is also regularly audited to maintain their accreditation.

What Information is Needed For Sap Calculations

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 Calculations For New Build

Every new property need Sap calculations to demonstrate compliance with Part L1A (Conservation of fuel and power in new dwellings) of the building regs.


Sap Calculations For Extensions

It’s now trendy to have large bi-folding doors, sky lights and large amounts of glazing on new extensions. But under the existing building regulations the quantity of glazing must be no more than 25percent of the floor area of the new extension. Therefore over compensations in the thermal elements in other areas of the property will have to be made to show the CO2 emissions from the current house and the proposed extension is no worse than the existing house and an extension where the glazing is within the permitted amount judged against Part L1B of the building regulations.

You should have SAP calculations to find solutions and show compliance.


Sap Calculations For Conversions

For anyone who is altering the use of a dwelling, you will require Sap calculations. {The new dwelling will have to comply with Part L1B of the building regulations.}


Will I Need Sap Calculations

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 checklist is not exhaustive. If you’re unsure whether you require them, then simply phone us.


Our Services

What You Can Expect From Us

Trusted & Experienced

Our Assessors are fully certified and accredited with many years experience carrying Sap calculation in Ealing . We also cover the whole of the UK and can help on any project nationally.

Reliable & Fully Insured

You will be allocated a dedicated Assessor who is also covered by full professional indemnity insurance of up to £100,000 so 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 seek to provide 100% customer satisfaction and look forward to working with you.


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