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SAP Calculations


We offer fast, affordable turnaround on your SAP assessment calculations. We offer this for new builds and extensions throughout the UK.

SAP calculations are an essential part of modern-day building regulations. We offer a fast and reliable service to sites and self-builds nationwide.

What Is A SAP Assessment?

SAP stands for ‘Standard Assessment Procedure’ and has been part of building regulations since 1995. SAP calculations are an official, government-approved system for assessing the energy rating of a newly built home. Consequently, a SAP report must be produced by an accredited and registered member of a certification body. Click here for a SAP assessment checklist.

There are two stages of SAP calculations:

  • Design stage
  • As built stage

Design stage – An initial review of the plans and drawings for the dwelling. They also take into account the details from the building design specification. This information allows for an estimated energy performance of the finished building. This is also known as a predicted energy assessment.

As built stage – As Built Sap bridges the gap between the design of the building on paper and the finished dwelling. It is common for details to alter throughout the build process. Due to this, the details from the design stage Sap must be updated to reflect the finished dwelling. Finally, once approved, an EPC Certificate can be released.

Separating the two stages of an SAP calculation is essential as this means that a building company or property owner has a better idea of the practicalities of their work. For example, suppose the design stage has a better level of energy efficiency than the as-built stage. In that case, there is an apparent discrepancy in the application of features of a building, such as insulation.

On the other hand, a company with better SAP ratings after the building process than at the design stage has lessons that it benefits from learning. For example, this demonstrates to a company that it benefits from using a particular type of insulation or a roofing method that it uses experimentally is more energy efficient than one it uses more commonly.

SAP assessments are highly accurate as SAP results are part of modern-day building regulations, and accredited institutions complete them. This is because assessors complete SAP assessment audits consistently, ensuring they have the skills to complete the task. In some instances, building companies request property retests after insulation changes and other aspects.

If you have any queries about what an SAP is and what an SAP entails, contact us today to learn more about the tests the process involves and how this applies to your building project and design.

What do SAPs tell me?

A SAP Rating is a way of comparing the energy performance of different homes; a figure will be generated between 1 and 100+ (with 100 representing zero energy cost and anything over means you have excess energy). Therefore, the higher the SAP rating, the lower the fuel costs and the more energy-efficient the home is.

This figure is based on the home’s construction, including its build specification, heating system, internal lighting, and renewable technologies. It does not include energy used for cooking or appliances. SAP calculations also provide a target for your Air Tightness test, ranging from 0 -10 m3.h/m2. This target score can be located on your initial compliance report.

When reading through an SAP test, the fact that the SAP test only considers the structural energy performance of the property is significant. This means that any appliances that the builder introduces to the property at a later point, such as cookers, washing machines and more, are not part of the considerations. This is especially important when considering systems that use hot water. This reduces the home’s efficiency, using energy for purposes outside of those that SAP tests consider.

Another critical aspect that builders note is that aspects such as CO2 emissions in the property are adjusted for floor area in the property. This means a more extensive property does not have issues due to more energy consumption. Instead, the size of the property offsets the carbon emissions and is an essential consideration in the overall result. The main goal of this offset is to avoid discouraging designers and builders from creating larger homes. An architect can create an energy-efficient design of any size and learn from the SAP rating, in the same way, implementing more energy-efficient solutions for the building.

Combining this with ventilation testing services benefits a designer, finding a balance between saving as much energy as possible and providing fresh air for any residents.

When should I get my sap calculations done?

Once you have a confirmed plan for the build, it is best to start! Early structural elements of the build dictate overall energy performance. It is much easier and cheaper to identify problems with the proposed build at the start than to make any alterations at the end.

Some of the issues that SAP tests find are fundamental to the property, with underlying issues such as the size of windows in the design meaning a potentially higher-than-normal rate of heat loss throughout a property. Finding potential issues with the design of a build at this stage means that an architect can change the design, add any necessary insulation and adjust design features to minimise heat loss throughout the building.

One of the benefits of using an SAP test from a reliable source is ensuring that the test is as quick and easy as possible. This is an integral part of the process as having fast results means that a designer benefits from using the feedback they receive as quickly and efficiently as possible. This means that the designer conveys the changes to builders, increasing energy efficiency at the start of the project and avoiding the high cost of retrofitting changes to the property.

This is unlike air tightness testing, which is ideal on a completed project so the testers can find the issues in a practical property.


Due to the unique aspect of SAP calculations, numerous factors result in non-compliance. However, there are a few simple tips to make compliance easier:

Maximise insulation; this includes both the thickness and quality to achieve low u-values for the calculation

Boiler controls, although the type of boiler makes a difference, simple controls such as Zoned heating and load/weather compensators are often neglected but can make a substantial difference.

Windows and doors, the lower the u-values of windows and doors, the better. With modern-day builds having more natural light, it is essential to ensure your windows are sufficient!
Air tightness all new builds are subject to an air tightness test, and this has a huge impact on your SAP calculations. If you pay attention throughout the build, it can help to make huge savings. Follow our helpful guides to achieve

Thermal bridging This is heat loss through junctions with external walls. Follow a scheme such as Accredited Construction Details (ACDs). This will allow us to avoid using default figures that usually overestimate the effects of these junctions.


Airtight testing Staffordshire is here to help you move quickly and easily through the process.
Our experienced sap assessors can offer expert advice to achieve compliance quickly and cost-effectively.

We can also offer a wide range of services to pass building regulations more efficiently than ever!