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

We would be pleased to offer you discount rates, for example for multiple dwellings that are of the same or very similar construction. For single dwellings then you would be looking in the region of £120 – £300 depending upon the complexity of the building along with the size. By supplying the plans, it will be possible to get a fixed quotation.

Before we get to the differences, this 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 buildings design that’s put together to display the energy effectiveness of a building. EPC means Energy Performance Certificate and it’s a summary report from the SAP calculations in an simple to grasp document, which could also be used to market or rent out a property.

There are really 2 types of EPCs. First is a SAP EPC which is created from building plans where all of the elements of the building are known. This will normally be required by building control to demonstrate that a property satisfies specific targets required by the building regulations. Building control would also have to see the SAP calculations which shows in greater detail whether all of the components going into your property conform to the building regulations.

The 2nd form of EPC is the typical one that would be necessary if you are marketing, or renting a property. This particular EPC uses what’s called rdSAP, which means Reduced Data Standard Assessment Procedure, which is used where certain thermal values of, for example, the walls, roof, floors, etc, are not precisely known on an existing property. In this situation assumed thermal values are used depending on the age of your property. This particular EPC would be no good to demonstrate compliance with any building regulations. Sometimes building control would simply ask you for an EPC, but what they would really need to have 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 call us for further information.

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

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, using approved Government software. The Assessor has to be certified under one of several certification schemes and is regularly audited to keep up their qualification.

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

It’s now quite fashionable to get large bi-folding doors, sky lights and large quantities of glazing on new extensions. However with the existing building regulations the amount of glazing can be no more than 25% of the floor area of the new extension. So over compensations in the thermal elements in other parts within the property will have to be made to demonstrate that the CO2 emissions coming from the existing house along with the planned extension is no 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 need SAP calculations to find solutions and illustrate compliance.

If you are altering 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. Give us a call, if you are unsure if you require them.