Chatham Top Sap Assessors

We undertake all sizes of residential projects needing SAP computations. All this at the best prices. Contact us to get a quotation for your project.

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

Sap Calculations, Exactly What Are They?

For anyone who is reading this, you’ve more than likely been recently asked by someone, typically your building control official, to provide sap calculations for your building project.

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



Chatham SAP Calcs For Dwelling Change Of Use

  • Reports for Part L1B Compliance
  • Free Advice

Chatham SAP Calcs For Overglazed Extensions

  • Carbon Emissions Reports
  • Heat Loss Calculations
  • Free Advice

Chatham 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 procedure for determining the energy efficiency of properties. These calculations are necessary to demonstrate that your building conforms with certain energy targets set down within the building regs.

In a brief overview, that’s essentially it.


When Are SAP Calculations Needed?

Some of the reasons you could 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 show that the dwelling emission rate (DER) and the dwelling fabric energy efficiency (DFEE) comply with specific targets.

The computations are carried out by a professional and accredited On Construction Domestic Energy Assessor. There is no need to visit the property as all of the computations are carried out from the building drawings . After the calculations are done, an Energy Performance Certificate or EPC can also be produced.

If the sap calculations show that your property is not compliant, then your Assessor will give you recommendations on upgrades which can be made to make it so. It’s very important to liaise with your Assessor as early on in your project as possible because once the building is completed any non-compliances might be quite costly to rectify.

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


Need an answer to a query you may have about SAP calculations in Chatham? Listed here are the ten most popular questions.

Sap Calculations, Exactly What Are They?

This really 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 Are Sap Calculations

The typical price range is between £100 – £300, this can be depending on the difficulty and size of your property. Should you also need an Energy Performance Certificate (EPC) at the end of it there may be an additional charge of about £50 to lodge the EPC on the epc register. For multiple dwellings of comparable designs, then discounts would be offered.

What’s The Difference Between Sap and EPC

Before we explain the difference, this is what you will need 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 performance of a property. An EPC or Energy Performance Certificate is a overview report derived from the Sap calculations which produces a SAP rating from 0 to 100. This rating is shown on the EPC as A the highest to G the lowest. It will also list suggestions which would improve the rating of your property.

There are really two types of EPCs. First is a SAP EPC that is created from building plans when all of the elements of the construction 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 also have to see the SAP calculations which shows in detail whether the many components going into your property comply with the building regulations.

The second type of EPC is the standard one that will be needed for anyone who is marketing, or renting a property. This kind of EPC uses what’s called rdSAP, which stands for Reduced Data Standard Assessment Procedure, and is used where specified thermal values of, for example, 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 your property. This sort of EPC would be no use to show compliance with any building regulations. Sometimes building control would simply ask you for an EPC, however what they would really need are the Sap calculations (which is the information behind the EPC) and the SAP EPC (which is actually summary report from the Sap calculations).

If you are still confused, after that contact us to get more assistance.

What Are As Built SAP Calculations

These are the finished set of SAP calculations created once the dwelling has been completed to hopefully demonstrate that it is compliant with Part L1A of the building regulations. Ahead of the construction starting, it should have had a set of “Design Sap” calculations to show that the proposed dwelling, on paper at least, would be compliant with Part L1A.



Can I Do The Sap Calculation Myself

No, this is not something you can do yourself. The calculations have to be carried out by an On Construction Domestic Energy Assessor or OCDEA, working with approved Government software programs. The Assessor has to be approved under one of several certification schemes and is also regularly audited to maintain 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

Every 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 amounts of glazing on new extensions. However under the present building regulations the quantity of glazing can be a maximum of 25percent of the floor area of the new extension. Therefore over compensations in the thermal elements in other parts of the property will need to be made to demonstrate that the CO2 emissions 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 allowed amount judged against Part L1B of the building regulations.

You should have SAP calculations to find solutions and demonstrate compliance.


Sap Calculations For Conversions

For anyone who is changing 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. If you’re unsure whether you need them, then simply 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 Chatham . 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.


Get A Quote, Or Call Us For Advice