Sap Calculations Hammersmith

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Sap Calculations, Exactly What Are They?

For anyone who is reading this article, you have more than likely been recently asked by somebody, typically your building control officer, to provide sap calculations for your building project. But you probably haven’t been told what sap calculation actually are and why you need them.

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



Hammersmith SAP Calcs For Dwelling Change Of Use

  • Reports for Part L1B Compliance
  • Free Advice

Hammersmith SAP Calcs For Overglazed Extensions

  • Carbon Emissions Reports
  • Heat Loss Calculations
  • Free Advice

Hammersmith SAP Calcs For New Builds

  • Reports for Part L1A compliance
  • Free Advice

What does SAP mean?

SAP is short for Standard Assessment Procedure and its the united kingdom government’s means of determining the energy performance of properties. These calculations are required to demonstrate that your building complies with certain energy targets set down within the building regulations.

As a brief overview, that’s pretty much it.


When Are SAP Calculations Needed?

Sap calculations usually are required for three main reasons

1. For all new properties
2. For a dwelling that’s changed its use, for example altering a commercial building to domestic flats.
3. For a planned extension having in excess of 25 % glazing

The sap calculations are necessary to show that the dwelling emission rate (DER) and the dwelling fabric energy efficiency (DFEE) conform to specified targets.

A good set of construction drawings will need to be provided to the Assessor, since 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. When the calculations are completed, an Energy Performance Certificate or EPC can also be produced.

Your Assessor can provide you with additional advice if the calculation show your building isn’t compliant, as well as advise you which is the most effective improvements to make. It is essential to liaise with the Assessor as early on in the project as possible because once the building is completed any non-compliances might be quite costly to rectify.

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


Need to have an answer to a query you may have about SAP calculations in Hammersmith? The following are the ten most common questions.

Sap Calculations, Exactly What Are They?

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

Sap Calculations, How Much Are They

We would be pleased to provide discount rates, especially for properties which are of the same or very similar design. For single dwellings then you would be looking in the region of £120 – £300 depending upon the difficulty of your building along with the size. By supplying the plans, you will be able to get yourself a fixed price quotation.

What Is The Difference Between Sap and EPC

Before we explain the difference, 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 properties design that’s created to demonstrate the energy effectiveness of a building. EPC is short for Energy Performance Certificate and it’s a summary report from the SAP calculations in an simple to comprehend report, that can also be used to market or rent a property.

There are really 2 types of EPCs. The first is a SAP EPC which is created from building plans where all of the components of the building are known. This would normally be required by building control to demonstrate that a dwelling satisfies certain targets required by the building regulations. Building control would must also see the SAP calculations which illustrates in detail whether all of the components going into the property conform to the building regulations.

The 2nd type of EPC is the common one that will be necessary for anyone who is selling, or renting out a property. This kind of EPC uses what’s called rdSAP, which is short for Reduced Data Standard Assessment Procedure, and is used where specific thermal values of, such as, the walls, roof, floors, etc, usually are not precisely known on an established property. In this instance assumed thermal values are used depending on the age of the property. This sort of EPC would 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 need to have are the Sap calculations (which is the information behind the EPC) and the SAP EPC (which is a summary report from the Sap calculations).

If you are still confused, then call us to get more assistance.

What Are As Built SAP Calculations

These are the final set of SAP calculations produced after the dwelling 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 dwelling, in theory at least, would be compliant with Part L1A.



How To Do Sap Calculations

Unfortunately this is not something you can do by yourself. The calculations need 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 certification schemes and is also regularly audited to keep their certification.

What Info 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

All new dwelling need 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 fashionable to have large bi-folding doors, sky lights and large amounts 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. Therefore over compensations on the thermal elements in other places of the property will need to be made to demonstrate that the CO2 emissions from the existing house along with the planned extension is not any worse than 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 illustrate compliance.


Sap Calculations For Conversions

When you are altering the use of a dwelling, you will need 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 not certain whether you require them, then give us a call.


Our Services

What You Can Expect From Us

Trusted & Experienced

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

Reliable & Fully Insured

You will be assigned a dedicated Assessor who is also covered by full professional indemnity insurance up to £100,000 and that 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 aim to provide 100% satisfaction and look forward to working with you.


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