The Shift from SAP to HEM: A New Era in Building Assessments

The transition from the Standard Assessment Procedure (SAP) to the Home Energy Model (HEM), set to be implemented alongside the Future Homes Standard in 2025, marks a significant shift in how energy performance is assessed in new homes. Announced in December 2023, the new system aims to provide more accurate and inclusive building assessments, with an increased emphasis on ventilation, energy efficiency, and overall sustainability. Originally, consultations were due to close on March 6, 2024, but the deadline was extended to March 27, 2024. This change responds to growing demands for more comprehensive and precise evaluations in light of evolving energy and environmental standards.

Why the change from the Standard Assessment Procedure (SAP) to Home Energy Model (HEM)?

The Standard Assessment Procedure was introduced in 1995 as part of building regulations. Considered innovative for its time, it provided a standardised approach to measuring a property’s energy efficiency, including factors like ventilation, insulation, and heating systems. Over the years, SAP has been updated to reflect changes in building practices and energy efficiency standards. Despite these updates, it has struggled to keep pace with evolving modern living patterns and doesn't sufficiently contribute to Net Zero goals.

One of the main limitations of SAP is its reliance on averaged data, which impacts the accuracy of energy assessments. SAP also fails to fully account for advanced technologies, such as automated systems, that enhance energy efficiency. Another key issue is its insufficient focus on modern ventilation strategies, which are essential for both health and energy efficiency. The new Home Energy Model aims to address these gaps by incorporating a broader range of products and building characteristics, driving higher energy performance and improved efficiency.

What are the differences between SAP and HEM?

The transition from SAP to HEM building assessments introduces key changes in how energy efficiency is evaluated. Here are the main differences between the two assessment frameworks:

Higher stadards

The Home Energy Model framework introduces stricter standards for building performance, with a key focus on more precise ventilation modelling to enhance indoor air quality. HEM places greater emphasis on thermal performance, aiming to minimise heat loss and improve insulation. The new system encourages the integration of renewable energy sources, promoting sustainable building practices and reducing energy waste. Introducing half-hour intervals for realistic energy consumption and environmental impact assessments (versus SAP’s monthly calculations) also contributes to a more accurate, up-to-date efficiency analysis. These updates align with the push towards higher energy efficiency and the goal of achieving Net Zero emissions in new homes.

Stricter compliance

Stricter compliance with Parts F and L of building regulations requires regular checks to ensure buildings meet ventilation and energy efficiency standards. Part F focuses on ventilation, ensuring healthy indoor air quality, while Part L addresses fuel and power efficiency, promoting reduced energy consumption. These regular checks not only support compliance but also promote sustained performance, improving energy efficiency and tenant wellbeing over time.

Distinguishing use cases with “wrappers”

With the main goal of HEM being increased clarity into a property’s energy efficiency, “wrappers” are to be introduced to help define different use cases and create a more intricate view of a building’s performance stats. A piece of code integrated as part of the software design, “wrappers” will help to define new use cases outside of the fixed standardisations and assumptions made by SAP software. With a more consistent application and simplified assessment criteria, “wrappers” will contribute to better decision-making and greater transparency.

Real-world performance

HEM prioritises actual data on energy use, ventilation effectiveness, and thermal performance, providing a more accurate representation of a building’s real-world energy usage. By incorporating real data from sensors and simulations, HEM ensures that buildings perform as intended in practice, rather than relying on averages and assumptions. This approach leads to more reliable assessments of energy efficiency, supporting better decision-making for sustainable building practices and achieving long-term energy goals.

Implementing HEM: Key steps

The HEM process involves several key steps to ensure buildings meet high energy efficiency standards. The initial assessment evaluates the current building performance, focusing on factors like insulation, ventilation, and energy use. Necessary system upgrades are then planned, particularly for enhancing ventilation and energy management. Finally, ongoing compliance and maintenance checks ensure the building continues to meet HEM standards, keeping it aligned with energy performance goals throughout its lifecycle.

Steps alongside HEM

Alongside the introduction of the HEM assessment model, digital building passports will become more commonplace. These act as a "living" document, designed to accurately track the entire lifecycle of a property. This digital passport can record everything from major upgrades, such as energy-efficient renovations, to routine maintenance tasks, using digital "stamps" to mark each update. The aim is to provide greater transparency, offering a clear, evidence-based record that can be accessed by property owners, managers, and regulators. This open model will help ensure ongoing compliance by creating a reliable, up-to-date record of a property’s history and condition.

How the change from SAP to HEM will impact property professionals

The shift from SAP to HEM will significantly impact property professionals, particularly landlords, property managers, and developers, who will need to take a more proactive approach to meet new energy efficiency standards. To stay ahead, they must integrate energy-efficient tools and technologies into property designs and builds, ensuring compliance with updated regulations. Clear documentation for regular compliance checks will be crucial, alongside periodic system assessments to verify ongoing energy performance.

Developers will also need to upgrade existing ventilation systems to meet stricter air quality and ventilation standards. This change is especially important given increased regulatory pressure, such as Awaab’s Law and the Warm Homes Plan, which emphasise the need for better ventilation and healthier living environments. Landlords, in particular, will face growing expectations to improve property ventilation, addressing both energy efficiency and tenant wellbeing. Proactively managing these changes will be essential for maintaining compliance and ensuring long-term sustainability in the housing sector.

Preparing for the transition

Preparing for the transition from SAP to HEM involves careful planning, particularly as the HEM framework will be fully implemented alongside the Future Homes Standard in 2025. Initially, the Future Homes Standard will apply only to new buildings, setting stricter energy efficiency requirements, including improved ventilation and thermal performance. Following the launch, HEM will be expanded to generate Energy Performance Certificates (EPCs) for existing properties, ensuring comprehensive energy assessments across the housing sector.

The government is currently refining the HEM framework through a consultation process, which may result in further adjustments before the official rollout. However, it's clear that technologies focused on smart ventilation, air quality, and heating controls will be crucial for housebuilders aiming to meet stricter building regulations. Property managers, landlords and developers should take a proactive approach now by integrating energy-efficient technologies into new builds, preparing for these regulatory changes and ensuring long-term compliance.

How Airflow can help

At Airflow, we understand that navigating the shift from SAP to HEM assessments and the evolving housing development regulations can be challenging. That’s why we specialise in mechanical ventilation with heat recovery (MVHR) and continuous running extractor fans, key solutions for developers and property managers aiming to improve energy efficiency in both social housing and private properties. As regulations tighten, it’s crucial to stay ahead of the curve.

Take a proactive approach to future plans and contact us today to learn more about our solutions that align with the latest assessment standards.