Social Housing Windows – Are We Retrofitting Right?

As the UK races towards its ambitious goal of net-zero emissions by 2050, the social housing sector faces a monumental challenge decarbonising existing buildings. The impending rollout of the Future Homes Standard (FHS) in January 2025 is set to accelerate progress, but the complexities, scope, and timescales of these new regulations present significant challenges. Mark Gajda, Head of Technical Services and Certification Manager at REHAU, explores what stakeholders should do to ensure compliance when retrofitting housing stock.

The Future Homes Standard has already caused major upheaval for the social housing sector. Adjustments made to Parts F and L of the Building Regulations in 2022, focusing on ventilation and energy efficiency remain a topic of discussion, with consultations and adjustments continuing long after the FHS was announced in 2019. 

Though these updated requirements were an interim measure, they have nonetheless placed local authorities and construction professionals under pressure even ahead of the planned FHS’s full adoption. Yet despite the upheaval, the goals of the FHS are laudable. Ensuring all new homes emit 75-80% less carbon than earlier benchmarks is essential for staying on track with the legally mandatory goal of net zero emissions by 2050. 

But considering 80% of current properties will still be in use by 2050 and most public housing was constructed between 1945 and 1980, the sheer magnitude of the task is clear. For effective upgrading to take place, social housing stakeholders will have to closely collaborate with their supply chain. This is even clearer in the context of the recent election and sector hopes that the incoming Labour government will allocate the Social Housing Decarbonisation Fund efficiently.

Preparing for 2025

The sense of urgency is compounded by the findings of REHAU’s market readiness report, Future Homes Standard: Preparing UK Housing for 2025. According to a survey of 200 decision-makers conducted by Censuswide, over two-thirds of the sector feel unprepared for the new standards. Worryingly, 79% of respondents said meeting the current FHS timeline would be ‘somewhat challenging’ or ‘very challenging.’

These are understandable concerns that likely underpinned the FHS consultation document launched in December 2023, which did not reduce the required 1.2 W/m²K u-value for frames as expected. Yet though this looks like a reprieve, focusing on u-values may lead stakeholders to overlook the wider benefits of the Home Energy Model the consultation proposes.

Rather than getting caught up in fluctuating performance metrics, stakeholders must adopt a holistic view of all building fabric components affected by the FHS. The introduction of the HEM, which replaces the outdated SAP10 assessment method, marks a shift towards this more nuanced approach. Different homes have unique requirements based on their location and environmental conditions. 

The HEM evaluates a building’s energy efficiency by assessing peak energy use in half-hour segments and considering local weather patterns. This allows for greater flexibility in component specification, accommodating a property’s unique characteristics. For instance, what works for a home in central London may not be suitable for one on the Cornish coast.

Frames and the Fabric

The importance of components like windows cannot be overstated in this context. Though windows significantly impact a building’s ventilation and thermal efficiency, awareness and confidence in finding frame systems that meet the FHS’s required u-value is low. According to REHAU’s whitepaper, 65% of respondents could not identify a frame system that meets this requirement, and the remaining 35% were uncertain. This gap underscores the need for cooperation across the supply chain to find and implement effective solutions, even if the HEM allows for extra leeway depending on location.

Indeed, the sector’s readiness for the FHS was a concern before the December 2023 consultation. The REHAU report showed that 76% of respondents working on new builds find the 2025 timeline challenging, with ‘cost,’ ‘supply chain issues,’ and ‘insufficient technical understanding’ cited as major concerns. Additionally, previous government revisions to building energy efficiency standards have raised doubts about the future of sustainability legislation. Though the election may alleviate these concerns, a new raft of policies and reviews from the incoming government could also muddy the waters further.

Working Together

Despite these challenges, social housing’s status as publicly owned property means there is greater pressure to evolve this building stock in line with increasingly rigorous energy efficiency legislation. Sector stakeholders must adapt, ensuring that all housing components contribute to meeting the upcoming standards. This includes leveraging the expertise of suppliers and collaborating closely with architects and specifiers.

Collaboration is key to navigating the FHS’s demands. By working together, specifiers can ensure that the most efficient and sustainable components suitable to differing property locations are chosen. This approach should extend beyond direct project stakeholders, to key component suppliers. Engaging with experts at the design stage means better-informed specification practices can be implemented early on, ensuring compliance with required thermal performance levels.

Consequently, decisionmakers within the social housing sector should conduct relevant research into their supply chains, assessing whether organisations within it can provide high-quality, compliant components. Doing so can also help specifiers avoid potential pitfalls. For instance, as mentioned under HEM, any selected frames must not only be high-performance but also appropriately specified considering the building’s structure and location. Close collaboration with suppliers can help address these issues and prevent potential errors.

With uncertainty surrounding the implementation of the FHS after the closing of the latest consultation in March, and the recent change in government, it is imperative that all parties are proactive about navigating the challenges ahead of the planned changes. This includes consulting with component providers about the HEM assessment model and its impact on individual parts of a building’s fabric. By integrating a holistic approach into specification processes, the industry can construct thermally efficient social housing fit for the future. The journey may be complex, but with the right partnerships and a commitment to innovation, the sector can achieve its net zero goals and contribute to a more sustainable future.