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Sap Calculations Harrow

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So, What Are Sap Calculations

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

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



Harrow SAP Calcs For Dwelling Change Of Use

  • Reports for Part L1B Compliance
  • Free Advice

Harrow SAP Calcs For Overglazed Extensions

  • Carbon Emissions Reports
  • Heat Loss Calculations
  • Free Advice

Harrow SAP Calcs For New Builds

  • Reports for Part L1A compliance
  • Free Advice

What does SAP mean?

SAP stands for Standard Assessment Procedure and its the united kingdom government’s way of determining the energy performance of properties. Sap calculations are needed to show that a building conforms with specific energy targets set down within the building regs.

In a quick overview, that’s pretty much it.


When Are SAP Calculations Needed?

Sap calculations usually are required for three main reasons

1. For all newly built dwellings
2. For a dwelling change of use, for example converting a commercial building to domestic flats.
3. For a planned extension having in excess of 25 % glazing

The 2 main areas which the sap calculations will look at is that the carbon emissions from your dwelling are within set tolerances and that certain elements of the property, such as the windows, roof, walls and floors comply with certain thermal energy targets.

Sap calculations are done by a certified and approved On Construction Domestic Energy Assessor. There is no need to visit the property because all the calculations are carried out from the building plans . When the calculations are done, an Energy Performance Certificate or EPC can also be created.

Your Assessor can provide further advice if the calculation show your dwelling isn’t compliant, as well as tell you which is the best changes to make. It may be costly if you find out at a late phase in the construction that your building isn’t compliant. So it is best to liaise with your Assessor as early on in the project as possible, ideally before any building commences.

Should you require advice on a project you could have in or around , or simply require a quote, contact us or fill in our get a quote form. We’re here to help.


Here we have presented the most common queries asked about SAP Calculations in Harrow.

So, What Are Sap Calculations

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

Sap Calculations, How Much Are They

If there are various properties with similar types of constructions, then reductions may apply. For individual properties then you would be looking in the region of £120 – £300 depending on the complexity of the building along with the measurements. By providing the plans, it will be possible to get yourself a fixed quote.

What Is The Difference Between Sap and EPC

Before we explain the difference, here is what you will need 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 calculations of pre defined data set of a properties design that’s created to show the energy performance of a building. EPC is short for Energy Performance Certificate and it’s a summary report of the SAP calculations in an simple to comprehend document, which can also be used to market or rent out a property.

There are actually two types of EPCs. First is a SAP EPC which is created from building plans where all the elements of the building are known. This would normally be required by building control to show that the property complies with specific targets essential to the building regulations. Building control would also need to see the SAP calculations which illustrates in greater detail whether all of the components going into the property comply with the building regulations.

The second variety of EPC is the standard one that will be required for anybody who is selling, or renting out a property. This particular EPC uses what’s called rdSAP, which is short for Reduced Data Standard Assessment Procedure, which is used where specific thermal values of, for instance, the walls, roof, floors, etc, usually are not precisely known on an established property. In this situation assumed thermal values are used based on the age of the property. This type of EPC would be no use to show compliance with any building regulations. Sometimes building control would simply ask you for the EPC, but 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 perplexed, then phone us for additional assistance.

What Are As Built SAP Calculations

These will be the finished set of SAP calculations produced after 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 show that the proposed dwelling, on paper at least, would be compliant with Part L1A.



How To Do Sap Calculations

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

What Info 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 need to have Sap calculations to show 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. However with the existing building regulations the amount of glazing must be no more than 25% of the floor area of the new extension. Therefore over compensations on the thermal elements in other parts of the property will have to be made to demonstrate that the CO2 emissions coming from the current house and the proposed 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 will require SAP calculations to find solutions and illustrate compliance.


Sap Calculations For Conversions

For anyone who is modifying 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 is not an exhaustive checklist. Phone us, if you are not certain if you require them.


Our Services

What You Can Expect From Us

Trusted & Experienced

Our Assessors are fully certified and accredited with years practical experience carrying Sap calculation in Harrow . We also cover the whole of the UK and can help on any job nationwide.

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


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