Enfield Sap Calculation Company

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Sap Calculations, Just What Are They

Have building control, or your architect requested that you get sap calculations. Why will you need them and exactly what are sap calculations anyhow? Then keep reading.

You can either click the video recording on this page, where Andreas will shed some light on this, or continue reading.



Enfield SAP Calcs For Dwelling Change Of Use

  • Reports for Part L1B Compliance
  • Free Advice

Enfield SAP Calcs For Overglazed Extensions

  • Carbon Emissions Reports
  • Heat Loss Calculations
  • Free Advice

Enfield 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 UK government’s means of calculating the energy efficiency of buildings. The calculations are needed to show that a building conforms with specified energy targets laid down in the building regulations.

That’s pretty much it in a brief overview.


When Are SAP Calculations Needed?

The three main reasons Sap calculations are needed

1. For all new homes
2. For a dwelling change of use,such as altering a commercial building to domestic flats.
3. For extensions that have over 20% glazing

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

A good set of construction drawings must be given 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. An EPC or Energy Performance Certificate can be produced once the calculations are done.

If your sap calculations show that your property is not compliant, then Assessor will give you guidance on improvements that may be made to make it so. It is essential to liaise with the Assessor as early on in the project as possible because once the building is finished any non-compliances might be quite costly to rectify.

If you need advice on a project you could have in , or require a quote, call us or fill in our get a quote form.


Here we have presented the most typical queries asked about SAP Calculations in Enfield.

Sap Calculations, Just What Are They

This is certainly by far the most common question asked. Take a look at Andrea’s video explanation above, or read the full explanation here on the right.

Sap Calculations, How Much Are They

The typical budget range will be between £100 – £300, this can be depending on the difficulty and size of the property. For those who also require an Energy Performance Certificate (EPC) at the end of it there could be another charge of about £50 to register an EPC on the national register. Special discounts would typically be available for a number of dwellings especially when they are of the identical style of building.

What Is The Difference Between Sap and EPC

Before we explain the difference, here 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 calculations of pre defined data set of a buildings design that’s created to display the energy performance of a dwelling. EPC stands for Energy Performance Certificate and it’s a summary statement of the SAP calculations in an easy to understand report, that could also be used to sell or rent a property.

There are actually two kinds of EPCs. The first is a SAP EPC that is created from building plans when all of the elements of the building are known. This would normally be needed by building control to demonstrate that the property complies with specified targets essential to the building regulations. Building control would also have to see the SAP calculations which illustrates in detail whether all of the elements going into the property conform to the building regulations.

The 2nd type of EPC is the typical one that will be necessary if you are selling, or renting a property. This kind of EPC uses what’s called rdSAP, which stands for Reduced Data Standard Assessment Procedure, and is used where specified thermal values of, such as, the walls, roof, floors, etc, usually are not precisely known on an existing property. In this case assumed thermal values are used depending on the age of the property. This type of EPC will be no use to demonstrate compliance with any building regulations. Sometimes building control would simply ask you for the EPC, however what they would really require are the Sap calculations (which is the data behind the EPC) and the SAP EPC (which is actually summary report of the Sap calculations).

Still confused, then simply call us for further information.

What Are As Built SAP Calculations

These are the final set of SAP calculations created when the building has been completed to show that it is compliant with Part L1A of the building regulations. Ahead of the construction starting, it ought to have had a set of “Design Sap” calculations to demonstrate that the proposed dwelling, in theory at least, will be compliant with Part L1A.



Can I Do The Sap Calculation Myself

No, this is not some thing you can do yourself. Sap calculations need to be done by an On Construction Domestic Energy Assessor or OCDEA, working with approved Government computer software. The Assessor has to be certified under one of the certification schemes and is regularly audited to keep their qualification.

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 to have Sap calculations to demonstrate compliance with Part L1A (Conservation of fuel and power in new dwellings) of the building regulations.


Sap Calculations For Extensions

It’s now quite modern to get large bi-folding doors, sky lights and large amounts of glazing on new extensions. However under the existing building regulations the amount of glazing must be a maximum of 25% of the floor area of the new extension. Therefore over compensations on the thermal elements in other parts of the property will need to be made to demonstrate that the CO2 emissions from the existing house along with 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 should have SAP calculations to find solutions and show compliance.


Sap Calculations For Conversions

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


Will I Need to have 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. Call us, if you are unsure if you need them.


Our Services

What You Can Expect From Us

Trusted & Experienced

Our Assessors are fully qualified and accredited with several years practical experience carrying Sap calculation in Enfield . We also cover the whole of the UK and can assist 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 to ensure 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% satisfaction and look forward to working with you.


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