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

This will can vary considerably depending upon the size and complication of the property, however a standard budget would be between £120 – £300. For those who also need an Energy Performance Certificate (EPC) at the end of it there could be another charge of about £50 to lodge the EPC on the register. Discounts would typically be available for multiple properties especially when they are of the identical type of construction.

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 calculations of pre defined data set of a properties design that’s put together to display the energy effectiveness of a building. EPC means Energy Performance Certificate and it’s a summary statement from the SAP calculations in an straightforward document, which could also be used to sell or rent a property.

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

The second type of EPC is the standard one that will be necessary for anybody who is selling, or renting out a property. This kind of EPC uses what’s called rdSAP, which means Reduced Data Standard Assessment Procedure, and is used where specified thermal values of, for instance, the walls, roof, floors, etc, usually are not precisely known on an existing property. In this case assumed thermal values are used based on the age of the property. This particular EPC would be no good to demonstrate compliance with any building regulations. Sometimes building control would simply ask you to get an EPC, however 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 give us a call to get more information.

These will be the finished set of SAP calculations created once the building has actually been completed to confirm that it is compliant with Part L1A of the building regulations. Ahead of the construction starting, it ought to have had some “Design Sap” calculations to demonstrate that the planned building, on paper at least, would be compliant with Part L1A.

Unfortunately this is not something that can be done yourself. The calculations need to be done by an On Construction Domestic Energy Assessor or OCDEA, using approved Government software programs. The Assessor has to be approved under one of several accreditation schemes and is regularly audited to keep their certification.

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 need Sap calculations to prove compliance with Part L1A (Conservation of fuel and power in new dwellings) of the building regulations.

It’s now quite popular to have large bi-folding doors, sky lights and large quantities of glazing on new extensions. But with the present building regulations the quantity of glazing must be a maximum of 25percent of the floor area of the new extension. Therefore over compensations on the thermal elements in other areas of the property will need to be made to show that the CO2 emissions from the current house and the planned extension is no worse than 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.

If you are modifying the use of a building, you will need 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. If you’re not certain whether you require them, then simply contact us.