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

We would be pleased to offer discount rates, in particular for multiple dwellings which are of the same or similar design. For individual properties then you would be looking in the range of £120 – £300 depending upon the difficulty of the building and also the measurements. By supplying the plans, you will be able to get yourself a fixed quotation.

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 calculations of pre defined data set of a properties design that’s created to show the energy efficiency of a building. An EPC or Energy Performance Certificate is a summary report created from the Sap calculations which produces a SAP rating from 0 to 100. This rating is shown on the Energy Performance Certificate as A the highest to G the lowest. It will also list recommendations that would enhance the rating of the property.

There are really two kinds of EPCs. The first is a SAP EPC which is created from building plans where all of the components of the construction are known. This would normally be needed by building control to show that the dwelling complies with specific targets essential to the building regulations. Building control would also need to see the SAP calculations which shows in greater detail whether the many elements going into your property conform to the building regulations.

The 2nd type of EPC is the common one that would be necessary for anyone who is selling, or renting out a property. This sort of EPC uses what’s called rdSAP, which stands for Reduced Data Standard Assessment Procedure, and is used where specified thermal values of, such as, the walls, roof, floors, etc, 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 good 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 information behind the EPC) and the SAP EPC (which is a summary report from the Sap calculations).

Still confused, after that phone us for further information.

These will be the final set of SAP calculations created after the building has 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 some “Design Sap” calculations to show that the planned building, in theory at least, would be compliant with Part L1A.

Unfortunately this is not something that you can do yourself. The calculations need to be done by an On Construction Domestic Energy Assessor or OCDEA, by using approved Government software programs. The Assessor must be certified under one of several accreditation schemes and is regularly audited to keep up 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 require Sap calculations to show compliance with Part L1A (Conservation of fuel and power in new dwellings) of the building regulations.

It’s now quite trendy to get large bi-folding doors, sky lights and large amounts of glazing on new extensions. But with the current building regulations the quantity of glazing must be a maximum of 25% of the floor area of the new extension. Therefore over compensations on the thermal elements in other parts of the property will need to be made to show the CO2 emissions from the existing house and the planned extension is no 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 will require SAP calculations to find solutions and demonstrate compliance.

For anybody who is 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 checklist is not exhaustive. Contact us, if you are unsure if you require them.