0800 046 7345 [email protected]

Sap Calculations Harrow

Prompt, reliable and most importantly very affordable Sap calculations for local residents and businesses. Call us today for a quotation on your job.

Get QuoteCLICK TO CALL FREE: 0800 046 7345
Air tightness testing
Water calculations

What Exactly Are Sap Calculations?

If you are reading this, you have probably recently been asked by somebody, usually your building control representative, to provide sap calculations for your building project.

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



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 is the united kingdom government’s method of determining the energy efficiency of dwellings. Sap calculations are necessary to demonstrate your building complies with certain energy targets laid down within the building regs.

As a simple summary, that’s basically it.


When Are SAP Calculations Needed?

Here are most of the reasons you may well be asked for sap calculations

1. For all newly built dwellings
2. For a dwelling that’s changed its use, such as altering a commercial building to residential flats.
3. For extensions that have more than 25% glazing

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

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

Your Assessor can give you additional advice if the calculation show your dwelling isn’t compliant, as well as explain to you which is the most effective improvements to make. It’s very important to liaise with the Assessor as early on in your project as possible because when the building is finished any non-compliances could possibly be quite costly to rectify.

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


Rather than trawl through a whole website to get the answers you’re searching for, we have supplied answers to the 10 most frequent questions asked about SAP in Harrow.

What Exactly Are Sap Calculations?

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

How Much Are Sap Calculations

If there are multiple properties with similar forms of constructions, then reductions may apply. For individual dwellings you would then be looking in the region of £120 – £300 depending upon the complexity of your design and also the size. By providing the plans, it will be possible to get a fixed price quotation.

What’s The Difference Between Sap and EPC

Before we get to the differences, 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 buildings design that’s created to display the energy performance of a building. EPC means Energy Performance Certificate and it’s a summary report from the SAP calculations in an simple to comprehend report, that could also be used to market or rent out a property.

There are actually 2 types of EPCs. First is a SAP EPC that is produced from building plans where all the components of the building are known. This will normally be required by building control to demonstrate that a dwelling complies with certain targets essential to the building regulations. Building control would must also see the SAP calculations which illustrates in detail whether the many elements going into the property conform to the building regulations.

The second variety of EPC is the standard one that will be required if you are marketing, or renting out a property. This kind of EPC uses what’s called rdSAP, which means Reduced Data Standard Assessment Procedure, which is used where particular thermal values of, for instance, the walls, roof, floors, etc, are not precisely known on an established property. In this case assumed thermal values are used based on the age of the property. This particular EPC will be no use to demonstrate compliance with any building regulations. Sometimes building control would simply ask you to get an 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 from the Sap calculations).

If you are still perplexed, after that contact us for further information.

What Are As Built SAP Calculations

These will be the final set of SAP calculations generated once the building has been completed to hopefully demonstrate that it is compliant with Part L1A of the building regulations. Prior to the building starting, it ought to have had some “Design Sap” calculations to demonstrate that the planned dwelling, on paper at least, will be compliant with Part L1A.



Can I Do The Sap Calculation Myself

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

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

All new dwelling require 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 popular to have large bi-folding doors, sky lights and large quantities of glazing on new extensions. But with the latest building regulations the amount of glazing must be no more than 25% of the floor area of the new extension. So over compensations on the thermal elements in other areas within the property will need to be made to show that the CO2 emissions coming from the current house and the planned extension is not any worse than the existing house and an extension whose glazing is within the allowed amount judged against Part L1B of the building regulations.

You need SAP calculations to find solutions and demonstrate compliance.


Sap Calculations For Conversions

When you are changing the use of a building, you will need 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 is not an exhaustive checklist. If you’re not certain whether you require them, then simply give us a call.


Our Services

What You Can Expect From Us

Trusted & Experienced

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

Reliable & Fully Insured

You will be assigned a dedicated Assessor who is also covered by full professional indemnity insurance up to £100,000 which means 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.


Get A Quote, Or Call Us For Advice