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Sap Calculations Hemel Hempstead

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Just what Are Sap Calculations?

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

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



Hemel Hempstead SAP Calcs For Dwelling Change Of Use

  • Reports for Part L1B Compliance
  • Free Advice

Hemel Hempstead SAP Calcs For Overglazed Extensions

  • Carbon Emissions Reports
  • Heat Loss Calculations
  • Free Advice

Hemel Hempstead SAP Calcs For New Builds

  • Reports for Part L1A compliance
  • Free Advice

What does SAP mean?

SAP is short for Standard Assessment Procedure and is the united kingdom government’s procedure for calculating the energy efficiency of properties. The calculations are needed to demonstrate your building conforms with certain energy targets laid down in the building regs.

In a short overview, that’s basically it.


When Are SAP Calculations Needed?

Sap calculations usually are required for three main reasons

1. For all new homes
2. For a dwelling that’s changed its use, such as converting a commercial building to residential flats.
3. For a planned extension having in excess of 25 % glazing

There are two main targets that the sap calculations are required to demonstrate. Firstly that the dwelling emission rate (DER) and the dwelling fabric energy efficiency (DFEE) comply with certain targets.

Sap computations are done by a certified and accredited On Construction Domestic Energy Assessor. There is not any need to visit the property as all the computations are carried out from the building drawings ,so a good set of plans are very important. An EPC or Energy Performance Certificate can be produced after the computations are done.

If your sap calculations show that your property is not compliant, then your Assessor will give you recommendations on improvements that can be made to make it so. It can be costly if you find out at a late stage in the construction that the building is not compliant. So it’s advisable to liaise with the Assessor as early on in the project as possible, ideally before any building commences.

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


Need an answer to a question you have about SAP calculations in Hemel Hempstead? Listed here are the 10 most common questions.

Just what Are Sap Calculations?

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

How Much Do Sap Calculations Cost

This will can vary considerably dependant upon the size and complication of the dwelling, but a standard price range will be between £120 – £300. There will probably be another fee of approximately £50 if an EPC is called for at the end of the construction. For multiple dwellings of comparable types, then discounts could well be available.

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 computations of pre defined data set of a properties design that’s put together to display the energy performance of a building. An EPC or Energy Performance Certificate is a overview report produced by the Sap calculations that produces a SAP score from 0 to 100. This score is shown on the EPC as A the highest to G the lowest. It will also list recommendations that would improve the rating of your dwelling.

There are really two kinds of EPCs. First is a SAP EPC which is created from building plans where all the components of the building are known. This will normally be required by building control to show that the dwelling complies with certain targets essential to the building regulations. Building control would must also see the SAP calculations which shows in detail whether all the elements going into the property conform to the building regulations.

The 2nd sort of EPC is the common one that will be required for anybody who is selling, or renting out a property. This type of EPC uses what’s called rdSAP, which stands for Reduced Data Standard Assessment Procedure, and is used where specific thermal values of, such as, the walls, roof, floors, etc, are not precisely known on an existing property. In this case assumed thermal values are used depending on the age of the property. This particular EPC will be no use to show 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 information behind the EPC) and the SAP EPC (which is actually summary report from the Sap calculations).

Still perplexed, then give us a call to get more information.

What Are As Built SAP Calculations

These are the final set of SAP calculations generated after the dwelling has actually been completed to hopefully demonstrate that it is compliant with Part L1A of the building regulations. Ahead of the project starting, it should have had a set of “Design Sap” calculations to show that the planned building, in theory at least, will be compliant with Part L1A.



Can I Do The Sap Calculation Myself

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

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 demonstrate compliance with Part L1A (Conservation of fuel and power in new dwellings) of the building regs.


Sap Calculations For Extensions

It’s now trendy to have large bi-folding doors, sky lights and large quantities of glazing on new extensions. But under the latest building regulations the amount of glazing can be a maximum of 25% of the floor area of the new extension. Therefore over compensations in the thermal elements in other places within the property will need to be made to demonstrate that the CO2 emissions coming from the existing house along with 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 will require SAP calculations to find solutions and demonstrate compliance.


Sap Calculations For Conversions

If you are altering the use of a dwelling, you will require 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 is not an exhaustive checklist. Call us, if you are not sure if you need them.


Our Services

What You Can Expect From Us

Trusted & Experienced

Our Assessors are fully certified and accredited with several years experience carrying Sap calculation in Hemel Hempstead . We also cover the whole of the UK and can help on any job 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 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% customer satisfaction and look forward to working with you.


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