Dwelling system level certification ​

As outlined by BRE in the state of the market report, integrated solutions or whole house retrofits are complex to certify, due to: 

• Multiple performance factors  
• Overlapping product warranties and certification 
• Boundary of product certification 
• Overlapping certification offerings and organisations in the market, at product level.

Dwelling system level certification has the following added complications: 

• No clear organisations exist that are capable of signing off at dwelling level vs product level. This is a major gap in UK capability highlighting a barrier to reaching retrofit at scale. 
• As highlighted by the Connected Places catapult, mass customisation is key to achieving retrofit at scale. This involves using combinations of variable kits-of-parts, at scale. 
  • How does industry expediate the process of certifying – at the dwelling level – for all the different combinations and iterations of kits-of-parts? 

• Certification at dwelling level for a portfolio of properties is critical for unlocking insurance and finance. 

As part of the Transform-ER UKRI programme, a certification event was held at MTC Liverpool in September 2025, attended by organisations involved and leading in this area. Positive and productive discussions led to consensus on these key points:   

• The current certification landscape is fragmented with inconsistent language and policy, and unclear timeframes and expectations.   

• We need to strengthen industry capability and SME support through consistent guidance, signposting and matchmaking to help innovators navigate the certification landscape – like ESC’s Sherpa Service.   

• Education for residents and installers needs to be improved through clear guidance to counter misinformation and negative publicity.   

Reaching an ideal future state for system level certification is a significant advancement from the industry current state. Therefore, the following points are speculative, to illustrate what an ideal state could be: 

• From the certification event held at MTC Liverpool in September 2025, discussions highlighted that, for the future of certification at a system level:  
  • We need a national ‘lily pad roadmap’ with a clear pathway from initial safety checks to provisional approval and full certification – with consolidated auditing roles and modular retrofit standards.    
  • Funding, procurement and insurance need to be aligned with certification to help absorb early risk.   

• For reaching retrofit at scale, a clear route for certifying variable combinations of retrofits, comprising of interoperable kits-of-parts for divergent portfolios of projects. 

• A certification framework for product developers to follow, outlining which organisations must be involved at specific stages in the process, e.g. BRE for Product Testing. 
  • This should include a hierarchy of certification and associated organisations. 

• Industry agreed criteria for system level certification. 
  • How do two different energy efficiency measures (EEMs) / retrofit products interact and how do you qualify this from a functional performance perspective, at system and product level? 
  • See also the Functional requirements checklist. 

To highlight the complexity of functions and stakeholders on this topic, Figure 1 shows the finance, regulatory and compliance ecosystem required for the dwelling system level certification to function.

Questions

• Mass customisation is key to achieving retrofit at scale, this involves combinations of variable kits-of-parts, at scale. 
  • How does industry expediate the process of certifying at the dwelling level, for all the different combinations and iterations of kits-of-parts? 
  • How do two different energy efficiency measures (EEMs) / retrofit products interact and how do you qualify this from a functional performance perspective, at system and product level? 

Enablers

• Industry route map to reaching system level certification for mass customisation of retrofit at scale and interoperable kits-of-parts. 
• We need a national ‘lily pad roadmap’ with a clear pathway from initial safety checks to provisional approval and full certification – with consolidated auditing roles and modular retrofit standards.    
• Funding, procurement and insurance need to be aligned with certification to help absorb early risk.