Do I Need an EPC or SAP?

f you’re confused about energy compliance, and aren’t quite sure what your legal responsibilities are, RS Energy is here to help. In this article, we go over what SAP and EPC actually are, if you need them, and what is required for different types of projects. 

So, do you need an EPC or SAP? SAP calculations are required for all new builds, some extensions, and some conversions, and informs the EPC certificate. SAP is rated from 1-100, which directly corresponds to the A-G system of EPC reports. EPC reports are legally required when a building is being sold, rented, or constructed. 

Read on to learn more about when you need a SAP report, or an EPC certificate.

Do I Need SAP Calculations or an EPC Certificate?

It is a legal requirement to conduct SAP calculations on all new build properties, as well as on some extensions and on conversions where the intended purpose of the building has changed significantly. The SAP calculation then informs the EPC certificate, with a SAP score form 1-100 directly corresponding to the A-G system of EPC certificates. 

You can learn more about how SAP scores are calculated, and what a good SAP score is here, in our recent blog. 

SAP EPC For New Builds

SAP calculations and an EPC certificate are required for all new build dwellings. Typically, energy compliance is assessed at the design stage, before building commences in order to save time and money further down the line. Effective planning at this stage means that energy compliance experts can provide advice on how to save energy, resulting in a better EPC certificate. 

When conducting a SAP assessment, we typically follow these steps:

  • Calculation of heat loss, including conduction and convection
  • Determining the amount of heat required to maintain a comfortable temperature inside the property
  • Determining the amount of energy required to provide hot water, heat and lighting. We also look at the efficiency of the boiler and other building services at this stage
  • Calculation of the cost of energy, based on standard fuel costs at the time of assessment
  • Calculation of C02 emissions, based on standard emission rates

Learn more about SAP calculations for new build properties in our recent blog.

SAP for Extensions

Not all extensions require a SAP assessment. This depends on the level of glazing that is included in the extension, and if plans meet other Building Regulations. Typically, glazing must account for no more than 25%, however there are nuances which offer a more flexible approach to glazing.

These nuances require that two other reports are considered; the Notional Report, and the Proposed Report.

Notional Report

This is where SAP calculations are made on the existing house, with an extension that is built exactly to Building Regulations, has glazing capped at 25%, and considers U Values.

Proposed Report

Next, SAP calculations are conducted for the property and extension as they will actually be built. To pass the assessment, you must prove that CO2 levels from the house and the extension, that will actually be built, must not exceed the CO2 levels detailed in The Notional Report. This ensures that the extension is energy efficient. 

Learn more about SAP calculations for extensions in our recent blog.

SAP EPC for Conversions

SAP assessments are typically required for conversions when the intended purposes of the building or room is significantly changed. This is called Material Change of Use. 

SAP calculations are required for conversions when:

  • If the building is being converted to be used as a home when it was not originally built for that purpose.
  • If the building being converted is to contain a flat, when it previously did not.
  • If the number of units in the building being converted has changed.

Changing a building  so that the new purpose is different from its original purpose means that the energy efficiency of the building will likely change. As such a SAP assessment needs to be conducted, and a new EPC report should be lodged. 

Learn more about SAP calculations for conversions in our recent blog.

When Would I Need an EPC Certificate?

Aside from the above situations, you would also legally be required to produce a valid EPC certificate in the following circumstances:

  • When a building is being constructed (as laid out above)
  • When a building is being sold – estate agents will usually not market your property until a valid EPC certificate is produced
  • When a building is being rented – all rented properties must have an EPC rating of E or above. The government has proposed that this will change to a rating or C or above by 2025. 

When Would I Need RdSAP?

RdSAP is derived from the same framework as SAP calculations, but is used to calculate EPC ratings for existing dwellings. The main purpose of RdSAP is to identify possible energy efficiency improvements, or if existing EPC certificates are no longer valid when a property is being sold or rented. 

Properties built after 6 April 2008 in England and Wales, 30 September 2008 in North Ireland, or 1 May 2007 in Scotland should have had a SAP assessment and an EPC certificate produced as standard, but older dwellings may not. EPC certificates expire after 10 years, so it is important to keep this in mind should you wish to sell or rent out your property. 

Learn more about RdSAP, and how it differs from SAP in our recent blog.

SAP EPC Calculations From the Energy Compliance Experts

RS Energy are providers of SAP calculations in England and across the UK to help you achieve regulatory compliance efficiently and cost-effectively. Our energy compliance experts can help you from design to build, ensuring that your development fulfils Building Compliance regulations.

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