Patent pending: unlocking retrofit innovation

Achieving net zero depends not just on how we build, but how we improve the homes we live in. This is particularly important at a time when at least 80% of buildings that will be occupied in 2050 have already been built, and the UK housing stock is among the least energy efficient in Europe. 

Retrofitting existing buildings is therefore essential to meeting the UK government’s commitment to net zero, a challenge industry is ready to respond to. However, innovation in this sector is often advancing faster than the systems designed to validate and approve them. New technologies, products, services and materials are needed for retrofit projects, however, there must be a clear path from idea to availability on the market.

BRE has joined several industry partners to launch RetroNetZero, an Innovate UK-funded Regulatory Science and Innovation Network (RSIN). The Network will analyse challenges that stakeholders encounter and where regulatory science (evidence, data, tools, standards) has a solution. Our team is working to help ensure that future regulation will support pro-innovation agendas and enable safe and consumer protected products.

This has taken shape through mapping the schemes and processes through which innovators bring a product to market. By pooling this resource into one location, we will improve transparency for innovators. 

At present, the route to adoption for domestic retrofit innovation is often complex and unclear. There are many schemes and processes to be navigated by innovators looking to scale-out their product, particularly when looking to tap into government funded and supported retrofit programmes. These include potentially achieving recognition through initiatives such as the Microgeneration Certification Scheme (MCS), Product Characteristics Database (PCDB) or SAP Appendix Q process, as well as understanding Building Safety Regulator and Office for Product Safety and Standards (OPSS) demands. Some products have specific requirements legally imposed by the UK’s Construction Products Regulations (CPR), while others rely on voluntary standards or self-declared performance data. Since leaving the EU, the UK has operated its own version of these regulations through the UKCA regime.

In January 2025, the EU updated its CPR framework to simplify what was regarded as an overly complex legal framework and ensure consistent implementation across member states. Crucially, the revised framework is closely aligned with broader EU sustainability initiatives like the Energy Performance of Buildings Directive, allowing construction products to directly support energy efficiency objectives and net zero objectives.

This is in contrast to the UK, where alongside current and upcoming proposed changes to the UK CPR, new retrofit technologies must navigate often-overlapping approval schemes and seemingly inconsistent requirements. It can pose a particular challenge given the drivers for domestic retrofit often involve government-funded schemes, which layer on additional indirect requirements on products and systems. Until now, there has been no single source of clarity on requirements for the sector.

In response, our first steps at RetroNetZero have been to provide a bird’s eye view of the current systems. We have consulted with both regulators and innovators to ensure a networked approach and allow for clear pathways to adoption to be available for all. 

We have built on the extremely useful work of the Energy Systems Catapult’s Innovation Accelerator project to publish detailed innovation adoption roadmaps showing the steps required to navigate various product approvals for retrofit. The roadmaps distinguish between what is mandatory, necessitated by key market drivers, and voluntary to help innovators prioritise their efforts. 

We have also created an online directory of organisations and facilities that could support companies through the required approvals processes – from testing laboratories and certification organisations to facilities offering product demonstration opportunities. So often, innovators do not know who to turn to support their product journey. The RetroNetZero directory will help broker important connections for those new to the sector and unfamiliar with who can help provide evidence and recognition of performance claims. 

The Network partners’ next steps have been to explore where opportunities exist to streamline or help innovators to navigate these pathways, and work is ongoing investigating a number of ‘challenge’ opportunities. These range from identifying systematic issues with sizing heat pumps that could deter consumers from switching to such systems, exploring how the associated co-benefits of retrofit products could be better promoted through regulation, and by providing supporting guidance on conducting field trials to demonstrate robust product performance for recognition processes such as SAP Appendix Q.  

When innovators can’t see a clear route to adoption, promising ideas stall and retrofit delivery lags. The result is fewer low-carbon technologies in homes, and a growing gap between the UK and its European counterparts. 

RetroNetZero is actively embedding regulatory science within the UK’s approach to retrofit. We want to ensure that innovators have a predictable path to market while maintaining the safety and quality of technology. That clarity is essential if the UK is to scale retrofit beyond pilot projects and turn technological progress into real, measurable carbon reductions.

RetroNetZero partners are comprised of BRE, Constructing Excellence, the Construction Products Association, the National Energy Foundation, the National Retrofit Hub and Planet Mark.

For further information and to get involved, please visit: https://retronetzero.uk/

This article first appeared in the April 2026 edition of Building Engineer.