Two key parliamentary committees – Climate Change and Science and Technical - have identified the decarbonisation of heat as the country’s single biggest challenge in the transition to net zero carbon emissions and have urged wider adoption of heat networks.

Heating specialists have pointed out that the performance of the HIUs connected to the heat networks is critical to their overall efficiency and effectiveness, but historically this issue was largely ignored.

A BEIS-funded research project conducted by consultant FairHeat found that poor performance of HIUs was one of the key drivers of the performance gap between design and actual performance of heat networks. Researchers concluded that it was difficult to limit network losses if the HIU performed poorly. The performance of HIUs was also a major determinant in the quality of heat delivery to residents.

Gareth Jones, chair of the UK HIU Steering Group, explained: “When considering heat network performance, most attention tends to be focused on the energy centre and the pipework in the basement of buildings that connects to the wider network. This is a mistake. Heat network efficiency starts (and often ends) with performance at a dwelling level. HIUs, which provide the interface to the wider network, are, therefore, critical.”

A new UK Test Standard for HIUs was developed by the Building Engineering Services Association (BESA). To address this knowledge gap and delegates at the forthcoming BESA National Conference will receive the latest updates on the test methodology, which is now being rapidly adopted by HIU manufacturers and heat network developers.

Mr Jones, who will chair the conference session at the Millennium Gloucester hotel in London, said: “Poor HIU performance has been the root cause of poor resident experience on several high-profile heat networks.

“In the past, there was no way to assess the relative performance of HIUs and there was often a significant discrepancy between the claims of manufacturers and the performance in practice. This meant that there was no way for those developing heat networks to make informed procurement decisions.”

The BESA standard was developed on behalf of consumers, which means the test regime places a heavy emphasis on the end user experience.

Mr Jones added: “The BESA Standard has also triggered a surge in research and development and we have direct evidence that significant improvements have been made in HIU performance that have all had a direct and positive impact on resident comfort.”