Energy Performance Certificates were first introduced in England in 2007, as part of a European Union drive towards more energy-efficient homes. Since then – and even though the UK isn’t part of the EU any longer – there have been a number of modifications to the types of certificates which can be issued.
One of the key distinctions which homebuilders, buyers and sellers need to be aware of are the differences between New-build and Standard EPCs. Assessment Hive, who provide new- build sap calculations across the UK, can supply both types of certificates; here we explain the key features of both.
The Methodology
All new-build domestic properties in the UK have to use SAP (Standard Assessment Procedures) to produce the relevant EPC. Existing properties use Reduced Data SAPs (RDSAPs) to collect the relevant information.
New-build SAPs rely on a wealth of technical data to determine how energy-efficient the property is. This includes detailed construction and service specifications including any drawings of floorplans and elevations, the type of insulation used, and how the hot water is generated. Another key element is the property’s air tightness – that is, how much heat is lost through the windows, doors, and through holes made for cables and pipes. For a fuller run-down of the information required, check out our previous blog post here.
SAPs set a target for the building’s emissions, energy consumption and efficiency (known as a notional building figure), then measure this against the actual figure.
RDSAPs are collected by an in-person visit from a domestic energy assessor, and they rely more on checking the visible elements of a property, rather than detailed plans and technical data. (Depending on the age of the property, and the type of records which were common practice at the time, a wealth of background information may not be as readily available).
The assessor will factor in the date the property was built, but they will still rely on the same type of information to produce the EPC – including what the walls (including Party walls) are made of, any insulation and glazing, and how the water (and rooms) are heated.
Whichever type of method is used, the property will be given a rating of A to G on the EPC, where A is the most energy-efficient and G is the worst. EPC certificates for new-builds are usually at the top end of the scale as they have been designed with energy efficiency in mind, and can take advantage of modern technologies to produce a more airtight building. (Commercial properties which require EPCs need a rating of E or above; so if it only has an F or G rating it will be illegal to let it out to a commercial tenant).
The Cost
EPCs which are produced from Standard Assessment Procedures are generally more expensive than their reduced data equivalents. This is because they collect more data and use a more complex set of calculations to determine the final EPC rating.
Also, SAPs take place more than once in the construction of a new property – once at the design stage, and once at the completion or ‘as built’ stage. The second may differ from the first as it typically has more detail – such as the model of the boiler or heat pump which has actually been installed and the actual airtightness which has been achieved.
However, it is worth noting that SAPs, as well as being potentially more accurate and comprehensive than their reduced data counterparts, have a much wider application. They can form the basis of BREL reports for new-build properties, and Basic Compliance Reports for conversions and extensions.
What About Extensions?
If you are planning to add an extension to your property, then it may need its own set of SAP calculations to comply with Building Regulations (and therefore will effectively be classified as a new-build).
However, it depends on the amount of glazing involved – as long as any areas of new glazing account for no more than a quarter of the extension’s new floor area (plus an allowance for existing windows that need to be removed) then you don’t need an additional calculation. At Assessment Hive we can provide a property SAP Assessment for your extension, should you require one.
Changes in the Regulations
However, the Government is planning to make changes to the certifications. An updated version of RDSAP and the calculations which will be involved is currently being worked on and should be available in the early part of this year.
The methods used to obtain an SAP rating are also due for a big overhaul in 2025 to bring them in line with the Government’s Future Homes Standard. It is expected they may include a bigger database on the types of heating equipment now on the market, as well as a more realistic assessment of any property’s energy efficiency during each half hour of the day. There may also be a change in the relevant Building Regulations.
At Assessment Hive we are constantly monitoring the situation and will be providing builders, homebuyers and sellers with information as soon as it becomes available.
New-build SAP Calculations in the UK from Assessment Hive
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