From SAP to HEM: The Future of UK Home Energy Performance Modelling

Retrofitting homes is central to the UK’s path to net zero, and the created opportunities are significant. If carried out correctly, we could unlock thousands of skilled jobs, lower energy bills, and create warmer, healthier homes for millions. But the cost of getting it wrong is just as significant. The current system, the UK’s Standard Assessment Procedure (SAP) for energy performance, is a blocker to adopting and scaling the necessary technology. It has proven itself outdated for modern low carbon technologies. The incoming Home Energy Model (HEM) will reshape how technologies are evaluated and, ultimately, which ones are deployed.

Innovation has an important role in realising the opportunities. The Government’s own plans recognise that over a third of the emissions reductions needed rely on technologies still under development . Without progress at pace and scale, the sector jobs won’t materialise, and millions of homes will remain cold and inefficient, particularly the UK’s estimated 10 million hard-to-treat properties where standard solutions aren’t suitable.

SAP is a key component of retrofit policy

Retrofit in the UK is heavily influenced by government policy, with most installations delivered through grant schemes with regulatory requirements rather than consumer demand. This means products must align with: 

• Energy performance methodologies
• Grant eligibility rules
• Installation standards and certification schemes

Frameworks like SAP (and its Appendix Q process), PAS 2035, and MCS certification all play a role in determining whether a product can access markets within public funding schemes, like the Warm Homes Social Housing Fund, and Local Grant which support the overwhelming majority of retrofit installations in the UK.

Compliance with these regulations is essential for ensuring all products in these markets are of high quality and so play an important role in consumer protection.  But these regulations are also complex to comply with, requiring significant investment from product manufacturers in both time and money to evidence that they do so. 

As a result, the development of many technologies can stall not because they lack potential, but because they can’t access the markets they need to grow. 

How will HEM change the landscape?

One of the most consistent challenges across the sector is the growing importance of evidence and data. This creates both risks and opportunities not just for innovators, but for all manufacturers, as established product providers increasingly look to optimise performance within HEM environments.

To gain recognition and uptake, products need to demonstrate their impact in ways that align with policy and regulatory requirements including:

• Robust test data
• Modelling across different building types
• Field trial evidence

Crucially, this evidence needs to be presented in a way policymakers and accreditation bodies can interpret and trust. By transitioning to HEM, innovators and manufacturers will have access to richer and more granular data, providing them with a stronger evidence base.

The SAP to HEM transition is developing quickly

Over the next few years, the government will deploy a phased approach from SAP to HEM to ensure a smooth transition period. 

Products that have been optimised for SAP may not perform in the same way under HEM. Equally, technologies that have struggled to demonstrate their value could benefit from a methodology that better reflects real-world performance, making early preparation essential. This highlights that market entry is not a one-off hurdle, but an ongoing process of adapting to policy change. Innovation is no longer just a technical challenge, but a strategic and regulatory one. It requires:

• Considering regulatory requirements earlier in product development
• Treating evidence generation as a core part of commercial strategy
• Understanding how policy decisions shape demand
• Engaging with the stakeholders who define standards and framework

Taken together, these considerations are not simply technical or compliance related; they are central to effective commercial strategy. Ensuring a product aligns with regulatory frameworks and evidential requirements is ultimately about securing access to target markets. Those that do this well are not just reacting to the system. They are positioning themselves to work within it, and in some cases, help shape it. 
 

Bridging the gap between innovation and adoption

There is no shortage of innovation, but a clear gap between what is technically possible and what is delivered at scale.

For organisations working in this space, some of the key questions are now:

• How do we get recognised with SAP or prepare for HEM?
• What level of evidence is needed and where do we focus effort?
• How do we position a product, so it aligns with funding mechanisms and policy priorities?
• Which stakeholders do we need to engage and when?

These are complex questions and getting them wrong can slow progress by months or even years.

We’re seeing more organisations look for support in bridging this gap by bringing together technical evidence, policy insight, and market understanding to create a clearer route to adoption.

If you’re currently thinking about how your product or solution fits into the UK retrofit landscape — or preparing for the transition to HEM — it’s a conversation worth having. Reach out for a chat to see how Talan can help.