This is by far the most common query asked. Check out Andrea’s video explanation above, or read the full explanation here on the right.

The typical price range will be between £100 – £300, this is depending upon the difficulty and proportions of your property. If you also need an Energy Performance Certificate (EPC) at the end of it there may be another charge of about £50 to lodge an EPC on the register. For multiple dwellings of comparable types, then discounts might be available.

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

There are actually two types of EPCs. The first is a SAP EPC which is created from building plans when all of the elements of the building are known. This would normally be needed by building control to show that the dwelling meets certain targets required by the building regulations. Building control would also need to see the SAP calculations which illustrates in detail whether all of the components going into your property comply with the building regulations.

The 2nd variety of EPC is the common one that will be necessary for anybody who is marketing, or renting out a property. This particular EPC uses what’s called rdSAP, which stands for Reduced Data Standard Assessment Procedure, and is used where specific thermal values of, for example, the walls, roof, floors, etc, usually are not precisely known on an established property. In this case assumed thermal values are used based on the age of your property. This type of EPC would be no use to show compliance with any building regulations. Sometimes building control would simply ask you for 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).

Still confused, then contact us for further advice.

These are the final set of SAP calculations produced after the dwelling has actually been completed to confirm that it is compliant with Part L1A of the building regulations. Prior to the project starting, it should have had some “Design Sap” calculations to show that the planned dwelling, on paper at least, would be compliant with Part L1A.

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

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)

Every new dwelling require Sap calculations to prove compliance with Part L1A (Conservation of fuel and power in new dwellings) of the building regs.

It’s now quite fashionable to have large bi-folding doors, sky lights and large quantities of glazing on new extensions. However under the latest building regulations the amount of glazing can be a maximum of 25percent of the floor area of the new extension. Therefore over compensations on the thermal elements in other places within the property will need to be made to show that the CO2 emissions coming from the current house and the planned extension is no worse than the existing house and an extension whose glazing is within the permitted amount judged against Part L1B of the building regulations.

You will need SAP calculations to find solutions and show compliance.

For anyone who is 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.}

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 list is not exhaustive. Contact us, if you are not sure if you need them.