As one of the largest contractors to work on residential retrofit projects funded by the Labour government’s Warm Homes Plan, chairperson and owner of principal contractor Sustainable Building Services (UK) Ltd, Derek Horrocks, reflects on the lessons learned from Social Housing Decarbonisation Fund (SHDF) Wave 2 and how we can achieve widespread success with Warm Homes: Social Housing Fund (WH:SHF) Wave 3.

The value of retrofit goes far beyond cost savings. An EPC rating is more than just a certificate - it can transform residents’ lives. From the health benefits of breathing cleaner air and staying warm in winter, to the reassurance of knowing your property is more energy efficient, reduces energy bills and provides comfort for your family, retrofit is about far more than reaching net zero targets.

As we continue the transition from focusing on SHDF Wave 2 to WH:SHF Wave 3, the question is: what should we take forward into this new phase? And how can the retrofit industry adopt a more consistent, collaborative approach that delivers long-term benefits for homes and families?

Resident engagement first

Retrofit can feel disruptive for residents, no access refusals from lack of understanding or poor engagement are the most common reasons why properties are removed from programmes. Early engagement with residents is therefore vital to smoother, faster delivery and project success.

Our dedicated resident liaison teams create household-specific engagement plans that are flexible, tailored and aligned to PAS 2035:2023. We take time to understand individual needs, identify vulnerabilities, explain the works and outline how each stage will affect residents.

Just as importantly, we ensure households know how to get the most from their newly installed energy efficient and renewable clean heat measures. When residents are listened to, supported and informed from the outset, projects run much more smoothly. Where communication falters, delays, disruption and mistrust can follow.

However, this responsibility doesn’t sit with contractors alone. Social landlords and community groups also need to work closely with tenants and local stakeholders to explain retrofit benefits, answer concerns and encourage participation.

Data-driven planning

To make Wave 3 as impactful as possible, we must learn from previous schemes. Better data collection is essential - both to reassure stakeholders and to give residents a clear picture of the real savings retrofit can achieve. Too often, predicated savings are based on incomplete or inaccurate pre-retrofit data, therefore this leads to a gap between predicted savings and actual performance, making post-retrofit monitoring and feedback critical for improvement.

Technologies such as Building Information Modelling (BIM) and in-home sensors can provide real-time data on thermal performance, indoor air quality and energy use. This not only supports continuous improvement but also gives residents reassurance and visibility.

Raising the bar with PAS 2035:2023

With the transition period for PAS 2035:2023 ending in March 2025, all Wave 3 projects must comply with these updated standards. Key changes include a new assessment criteria (including RdSAP10), an airtightness, ventilation and moisture strategy, new designer guidelines and on-site coordination.

As a member of the PAS Steering Group that helped shape these updates, I am already seeing the benefits on site. At SBS, we are already delivering Wave 3 PAS-compliant schemes at scale, across social and private properties.

The updated standards place greater emphasis on on-site quality, effective resident engagement, coordinated design and consistent assessments. In practice, this is raising standards for both residents and contractors – creating a more reliable, collaborative approach across Wave 3.

Stronger communication

Successful retrofit relies on communication and collaboration. Projects involve a wide range of stakeholders – landlords, residents, contractors, PAS role providers and regulators – and multiple trades and technologies. Managing this complexity is essential to avoid delays, increased costs and dissatisfaction.

Clear alignment on goals, timelines, scope and requirements from day one is crucial.

At SBS, we’ve found that our resident liaison officers (RLOs) play a particularly effective role. Often part of the communities they serve, RLOs understand local dynamics and challenges. We hold regular meetings with RLOs across the UK to share best practice, resolve common issues and identify new opportunities. This regular exchange ensures stronger communication between contractors, councils, stakeholders and residents, driving better outcomes and wider social value.

The case for an area-based approach

Retrofitting at scale demands systemic, joined-up models rather than piecemeal projects. Area-based schemes enable economies of scale, more effective community engagement and streamlined logistics.

With our first Warm Homes: Social Housing Fund Wave 3 and Warm Homes: Local Grant project involving more than 700 properties across social and private tenures in North East Derbyshire, we remain focused on delivering integrated, community-first retrofit schemes. Area-based approaches allow for shared logistics, coordinated engagement, efficiencies, cost savings and collective knowledge - benefits that cannot be achieved in isolated projects.

Plan ahead to avoid bottlenecks

The most important lesson from Wave 2 is the need to plan early, clients must act to secure the right contractors able to deliver turnkey end-to-end solutions. Mobilising assessments, procurement and installation at the earliest stage is essential to avoiding potential bottlenecks and ensuring successful, compliant delivery.

Wave 3 is more than another funding round; it’s an opportunity to transform communities and embed sustainable change for decades to come. If we fail to act with urgency, collaboration and foresight, the window will close. But if we get it right, we won’t just improve homes - we’ll change lives, strengthen communities and set a new standard for what retrofit can achieve.