SAP calculations are mandatory under the Building Regulations for newly constructed dwellings in Northern Ireland. A SAP Rating has been obligatory for new homes under Part F1 of the Technical Booklet of the Northern Ireland building legislation since 2012. A revised version of that was issued in 2022. Hence, most developers and architects are acquainted with it.

Nevertheless, for many home owners it may present a new and frequently daunting element of the design and building process.

What is the purpose of a SAP Assessment?

SAP assessments serve three main purposes:

1. They establish a SAP Rating. This is the projected estimate of the energy-related costs and the carbon emissions of the new dwelling

2. They provide a compliance platform with Part F1 of the building regulations

3. They are used to generate the Energy Performance Certificate (EPC) of the new dwellings using architects’ drawings.

SAP, which stands for ‘Standard Assessment Procedure’, is the sole official and government-approved system used to evaluate the energy rating of a new home. SAP assessors must obtain a qualification and then register with an accreditation scheme.


As mentioned above, SAP assessments of new builds produce the EPC which is a numerical value ranging from 1 to 100 where 100 signifies zero energy cost and anything above indicates energy exportation. A higher EPC rating corresponds to lower fuel expenses and reduced carbon dioxide emissions.

Why SAP assessments are important to new home owners

Here are a number of reasons why SAP assessments are important to homeowners:

• To get planning approval, or to get a new build approved by Building Control, you must obtain a 'pass' on your SAP Calculations.

• It is advisable to work with a SAP assessor at the design stage so that any potential non-compliances are addressed before you start building

• The SAP Calculations will determine the projected energy cost of a home based on its construction, heating system, lighting, and any installed renewable technologies.

• Mortgage companies require a copy of the EPC report produced via the SAP assessment

• A SAP assessor can assist the architect in optimizing the energy efficiency and reducing carbon emissions of a new dwelling.

How to Ensure Compliance

Achieving a 'pass' in your SAP assessment involves meeting various compliance targets. Here are a few things that help a proposed new build pass a SAP assessment.

• Ensure low u values of walls, floors and roofs. This is related to the insulation and heat retention capabilities of the dwelling's structure. This is formally known as u values of the building envelope.

• Take into consideration the u values of windows and doors and ensure u values of 1.4 W/m2K or lower.

• Ensure efficient heating systems as well as heating controls, such as zoned heating

• At completion, ensure that the building is airtight by conducting an airtightness test. We recommend a target of 5m³/hr/m². This score is better than the average house in the UK. However, it is achievable when using modern building technologies.

• Leverage on solar energy where possible with the use of PV panels.

Various factors, such as boiler size, wall junctions, insulation thickness, and orientation of the house, can influence whether a proposed new dwelling will pass or fail a SAP assessment.

Factors beyond the client's control, like the absence of a mains gas connection leading to the use of oil, or LPG heating systems, can impact costs and CO2 emissions within SAP. It is important to consider these factors when working with the architect and the SAP assessor

Remember, it is advisable to conduct a design stage SAP assessment before starting any building work.