SAP calculations perform a vital role in the design of residential developments, conversions and some extensions in the UK and are essential for passing Building Regulations.

Aside from it being a legal requirement, however, this post aims to uncover further reasons why SAP calculations are so important.

Read on to find out more…

SAP calculations ebook | Sustain quality

SAP Calculations And Building Regulations

Since 1995, a SAP rating has been required for all new homes under Part L of the Building Regulations. Current building regulations state that home builders will need to gain a ‘pass’ on their SAP calculation, and without it, building control won’t sign off the development.

If Building Control doesn’t sign off the development, the property may not legally be listed for rent or sale.

SAP Calculations Are Crucial Way Before Project Completion

We strongly advise you hire the services of an experienced SAP assessor during the early phase of your built project. This will shape the energy performance and consumption. A SAP Assessor during the design stage will ensure SAP compliance, and most importantly, reduce the number of surprises further down the line.

Getting a SAP assessor way before project completion will allow them to work alongside the designer or architect, ensuring the accurate prediction of the running costs of the home.

Enabling Climate Action Through SAP Solutions

Of course, SAP calculations help reduce carbon outputs and contribute to our goals for sustainable developments. Using digitalisation, SAPs can help to combat the damage caused by climate change.

To quote SAP Chief Sustainability Officer, Daniel Schmid,

“SAP’s key lever is our product portfolio, with which we enable customers to create positive economic, environmental, and social impacts. If we look at our broad reach, the potential for us to make a difference could be enormous.”

SAPs Inform the EPC

A SAP rating broadcasts the energy performance of the property, which in turn informs the Energy Performance Certificate (EPC). The EPC is what all buyers and tenants see.

A pass is gained by meeting compliance targets around:

  • The fabric and how well it contains heat
  • Solar gain
  • Quality of construction and commissioning of systems
  • Predicted CO2 emissions from the dwelling

SAP Calculations are Important For Extensions & Conversions

For extensions, a SAP calculation will depend on how much glazing is incorporated. If the new glazing exceeds 25% of the total floor area of the new extension, then you’ll need to get a SAP calculation carried out.

As homeowners prefer to build extensions that let in a lot of light, SAP calculations are common in extensions.

For conversions, SAP calculations are only required if the conversion results in a ‘Material Change of Use’ or a ‘Change of Energy Status’.

A material change of use refers to a property that is changing its purpose for which the building is used. For example, converting a dwelling into flats.

A change in energy status refers to buildings or spaces that have not previously been heated but have changed to be heated.

If either or both of these changes occur, then you will need to get SAP calculations for your conversion.


To summarise, SAP calculations are important due to a number of factors. For example:

  • To comply with building regulations
  • To help inform the designers’/architect’s practices
  • To reduce CO2 emissions and carbon outputs
  • To inform the EPC

If you would like to find out more about our SAP calculation services or would like to speak to one of our team members about energy advice for your property, get in touch on 01372 438 039 or fill out the form below and we’d be more than happy to help.

Did you read our previous blog on, What Is A SAP Calculation? Click here to read it now.

SAP calculations ebook | Sustain quality

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About Us

We are a friendly team of Engineers delivering Sustainability and Building Compliance Solutions for developments in the Commercial and Residential sectors, which include Energy Statements, Noise Impact and Vibration Assessments, BREEAM Assessments, and Air Quality Assessments in the Environmental, Social and Governance sectors.

Contact us at:

Sustain Quality Ltd

PO Box 393


KT11 3EL

01372 438039