What Is the Home Energy Model (HEM)?

The Home Energy Model (HEM) is the UK government’s upcoming replacement for the Standard Assessment Procedure (SAP) the current official method used to evaluate the energy efficiency of buildings.

Developed in line with the Future Homes Standard, the HEM will deliver more accurate, real-world calculations to help the country transition to net-zero carbon buildings.

While SAP has served the industry for decades, its limitations in modelling low-carbon homes and real-life performance have led to the development of this next-generation assessment tool.

When Will the Home Energy Model Be Introduced?

Although initially scheduled for 2025, the rollout of the Home Energy Model is now expected to align with a revised 2026 launch alongside the Future Homes Standard.

Importantly, SAP remains the current requirement for compliance with Part L of the Building Regulations. UKBC will continue to provide certified SAP assessments while preparing clients for a smooth transition to HEM.

What’s Changing with HEM?

The Home Energy Model brings key innovations that aim to improve accuracy and adapt to modern, low-carbon building technologies:

• Real-world performance emphasis

• Half-hour energy modelling intervals (vs. SAP's monthly averages)

• Thermal zoning, allowing detailed heat loss calculations per building section

• Integration of local weather data and household appliance ratings

• A more transparent, evidence-based structure

• Enhanced database of building products and technologies

These changes are designed to better reflect actual energy use and support future-proofed home designs.

How Does This Affect Your Project?

Whether you're planning a new build, extension, or conversion, the Home Energy Model will soon become the standard. But there’s no need to delay your project — SAP assessments are still valid and required.

At UK Building Compliance, we stay ahead of regulatory changes so you don’t have to. Our assessors are trained and ready to deliver accurate, detailed SAP reports today and will transition to the Home Energy Model as soon as it is formally introduced.

Why Choose UKBC?

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Stay compliant, stay ahead. Whether you're working under the current SAP framework or preparing for the upcoming HEM standards, UKBC has you covered.