Future Homes Standard & SAP 10.3

The Future Homes Standard introduces the next major change to energy-efficiency requirements for new homes in England. The new requirements are intended to deliver highly energy-efficient homes with low-carbon heating and greater use of renewable electricity generation.

The new regulations are due to come into force on 24 March 2027, subject to transitional arrangements. Until then, projects falling under the current Part L 2021 requirements continue to be assessed under the applicable existing compliance route, including SAP 10.2 where appropriate.

For projects that will fall under the new requirements, considering SAP compliance early can help architects, developers and project teams understand how decisions relating to the building fabric, heating, ventilation and renewable technologies may affect the assessment.

What Is the Future Homes Standard?

The Future Homes Standard forms part of the 2026 changes to the Building Regulations in England and introduces updated requirements for the energy and greenhouse-gas performance of new dwellings.

The changes are designed to reduce reliance on fossil fuels and ensure that new homes are suitable for a future increasingly supplied by low-carbon electricity.

The updated regulations and Approved Document L introduce changes affecting areas including:

Energy efficiency and greenhouse-gas emissions
Low-carbon heating systems
Building fabric performance
Building services and controls
On-site renewable electricity generation
Commissioning and installation of building services
Information provided to homeowners

A new Requirement L3 also introduces a requirement for on-site renewable electricity generation for new dwellings, subject to the provisions contained within the regulations and Approved Document L.

When Does the Future Homes Standard Apply?

For most new residential building work in England, the new requirements come into force on 24 March 2027.

However, transitional arrangements mean that some projects may continue under the previous requirements.

For non-higher-risk building work, projects may remain under the previous regulations where the relevant building notice, initial notice or full-plans building control application was made before 24 March 2027, provided the relevant building work is commenced before 24 March 2028.

This makes the project programme and Building Control submission date important when establishing which version of Part L applies.

Projects should therefore establish the applicable Building Regulations requirements before deciding which SAP methodology and compliance standard should be used.

SAP 10.2 and SAP 10.3 – What Is the Difference?

SAP 10.2 is associated with the current Part L 2021 compliance regime and continues to be relevant to projects proceeding under those requirements.

SAP 10.3 is the updated version of the Standard Assessment Procedure developed to support the new Future Homes Standard requirements.

SAP remains the methodology used to calculate the predicted energy performance of a dwelling and considers factors including:

Building dimensions and exposed areas
Insulation and U-values
Thermal bridging
Airtightness
Windows, doors and glazing
Heating and hot-water systems
Ventilation
Renewable technologies
Energy use
Carbon emissions
Primary energy

The assessment compares the proposed dwelling against the relevant regulatory targets and notional dwelling.

The important point is that SAP 10.3 being published does not mean every project should immediately be assessed against the new Future Homes Standard. The applicable Building Regulations and transitional arrangements still need to be established for each project.

What About the Home Energy Model?

The Government is developing the Home Energy Model (HEM) as the longer-term replacement for SAP.

HEM was originally intended to be introduced alongside the Future Homes Standard, but its launch has been delayed while further assurance and development work is completed.

SAP 10.3 is therefore currently the approved methodology available for demonstrating compliance with the Future Homes Standard, with HEM expected to be introduced alongside it at a later stage.

The Government ultimately intends HEM to replace SAP, but SAP 10.3 will remain an important compliance methodology during the transition.

What Will the Changes Mean for New Homes?

The Future Homes Standard places greater emphasis on considering the performance of the dwelling as a complete system.

Building fabric, heating, ventilation, renewable generation and building services all interact within the assessment.

This means that decisions made early in the design can influence the eventual compliance result.

For example, changing glazing areas, U-values, thermal bridging, heating systems, ventilation or renewable technologies can alter the SAP assessment. Looking at these elements before the specification is fixed can provide more options than trying to resolve a compliance problem once construction has started.

The End of Gas Boilers in New Dwellings

One of the most significant changes under the Future Homes Standard is the move away from fossil-fuel heating in new homes.

The new standard is designed around low-carbon heating. Government guidance states that gas boilers, including hydrogen-ready boilers and hybrid systems, will not meet the required performance standard for new dwellings.

In practice, new homes will therefore need to use low-carbon heating solutions, such as heat pumps or suitable low-carbon heat networks. The Government has confirmed that gas boilers will not meet the required performance standard under the Future Homes Standard.

On-Site Renewable Electricity

One of the significant changes is the introduction of the new Requirement L3 relating to on-site renewable electricity generation.

Approved Document L provides a method for determining the required level of renewable electricity generation for a dwelling, with photovoltaic panels forming the reference approach used within the guidance.

The exact solution will depend on the project and the requirements of the regulations.

For SAP purposes, the proposed renewable system and its performance are included within the dwelling assessment alongside the building fabric and services.

Why Early SAP Assessment Matters

Waiting until the specification is complete before carrying out the first SAP assessment can reduce the number of practical options available if the dwelling does not initially comply.

An early Design-Stage SAP assessment can help identify which parts of the proposed specification have the greatest influence on performance.

Where changes are required, alternative options provided by the project team can then be modelled to understand their effect on the assessment.

This can help project teams make informed decisions without automatically increasing insulation levels, changing products or adding technologies that may provide little benefit to the final compliance result.

Preparing Projects for the Future Homes Standard

Projects expected to fall under the new requirements should consider the energy strategy early in the design process.

Useful information for an initial assessment may include architectural drawings, construction specifications, proposed U-values, glazing information, heating and hot-water systems, ventilation strategy and proposed renewable technologies.

Not every detail needs to be finalised before an assessment begins. Early modelling can instead be used to identify areas that may require further consideration as the design develops.

How Crowther Solutions Can Help

Crowther Solutions provides SAP calculations and residential Building Regulations compliance support for projects across the UK, with experience in energy assessment and construction dating back to 2005.

For projects affected by the Future Homes Standard, we can assess the proposed dwelling, identify the factors influencing compliance and model alternative options provided by the project team.

Our role is to provide the assessment and technical compliance guidance. The final design, product selection and specification remain the responsibility of the appointed designers and project team.

Starting the SAP process early gives the project team more opportunity to understand the effect of design decisions before they become difficult or expensive to change.

Need Advice on an Upcoming Project?

If you are planning a new residential development and are unsure whether the current Part L requirements or the Future Homes Standard will apply, send us the project information and proposed programme.

We can review the available information, establish the appropriate SAP assessment route and provide a project-specific quotation.

Request a SAP Calculation Quote