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So, What Are Sap Calculations

Have building control, or your architect requested you to get sap computations. But why will you need them and just what are sap calculations anyhow? Then continue reading.

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



Chelmsford SAP Calcs For Dwelling Change Of Use

  • Reports for Part L1B Compliance
  • Free Advice

Chelmsford SAP Calcs For Overglazed Extensions

  • Carbon Emissions Reports
  • Heat Loss Calculations
  • Free Advice

Chelmsford SAP Calcs For New Builds

  • Reports for Part L1A compliance
  • Free Advice

What does SAP mean?

SAP stands for Standard Assessment Procedure and it is the UK government’s way of determining the energy performance of properties. The calculations are necessary to prove your building conforms with specified energy targets set down within the building regulations.

That’s pretty much it in a quick overview.


When Are SAP Calculations Needed?

Here are most of the reasons you will be asked for sap computations
1. For all newly built properties
2. For a dwelling change of use, for example changing a commercial building to flats
3. For extensions that have more than 25% glazing

The sap calculations are required to demonstrate that the dwelling emission rate (DER) and the dwelling fabric energy efficiency (DFEE) comply with specified targets.

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

If your sap calculations reveal that your property isn’t compliant, the Assessor will give you advice on upgrades which can be made to make it so. It may be costly if you realise at a late phase in the construction that the building isn’t compliant. So it’s wise to liaise with your Assessor as early on during the project as possible, ideally before any building commences.

If you require advice on a project you may have in or around Chelmsford , or simply require a quote, give us a call or fill in our get a quote form. We’re here to help.


Sap Calculations Questions, See Whether We Have An Answer Below.

So, What Are Sap Calculations

This is quite possibly the most frequent question asked. Take a look at Andrea’s video explanation above, or read the full explanation here on the right.

How Much Do Sap Calculations Cost

This can vary considerably dependant upon the measurements and complexity of the property, however a typical budget would be between £120 – £300. There may be an extra cost of about £50 if an Energy Performance Certificate is called for at the end of the construction. For several properties of similar designs, then discounts might be available.

What’s The Difference Between Sap and EPC

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

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 properties design that’s created to display the energy performance of a building. An EPC or Energy Performance Certificate is a overview report derived from the Sap calculations that produces a SAP score from 0 to 100. This score is expressed on the Energy Performance Certificate as A the highest to G the lowest. It will also list recommendations that would increase the rating of your property.

There are really two types of EPCs. First is a SAP EPC which is created from building plans where all of the components of the construction are known. This would normally be required 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 components going into your property comply with the building regulations.

The second type of EPC is the typical one that would be needed when you are marketing, or renting a property. This type of EPC uses what’s called rdSAP, which means Reduced Data Standard Assessment Procedure, which is used where certain thermal values of, such as, the walls, roof, floors, etc, are not precisely known on an existing property. In this instance assumed thermal values are used according to 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 to get an EPC, however what they would really need are the Sap calculations (which is the data behind the EPC) and the SAP EPC (which is actually summary report from the Sap calculations).

If you are still confused, then simply phone us for further advice.

What Are As Built SAP Calculations

These will be the finished set of SAP calculations produced after the building has been completed to confirm that it is compliant with Part L1A of the building regulations. Prior to the construction starting, it ought to have had some “Design Sap” calculations to demonstrate that the planned construction, in theory at least, would be compliant with Part L1A.



Can I Do The Sap Calculation Myself

No, this is not something that you can do by yourself. The calculations must be carried out by an On Construction Domestic Energy Assessor or OCDEA, by using approved Government software. The Assessor needs to be approved under one of several accreditation schemes and is regularly audited to keep their qualification.

What Information is Required 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 require Sap calculations to prove 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 have large bi-folding doors, sky lights and large quantities of glazing on new extensions. However with the present building regulations the quantity of glazing must be no more than 25% of the floor area of the new extension. So over compensations in the thermal elements in other parts within the property will have to be made to demonstrate that the CO2 emissions from the existing house and the planned extension is not any worse when compared to the existing house and an extension whose 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

When you are altering the use of a building, you will need Sap calculations. {The new dwelling will have to comply with Part L1B of the building regulations.}


Do 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. Give us a call, if you are not certain if you need them.


Our Services

What You Can Expect From Us

Trusted & Experienced

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

Reliable & Fully Insured

You will be assigned a dedicated Assessor who is also covered by full professional indemnity insurance 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 aim to provide 100% satisfaction and look forward to working with you.


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