FairHeat’s Associate, Tom Naughton, discusses the initiatives and processes that are transforming the way residential heat networks are being delivered.

It’s no secret that heat networks have had a bumpy ride over the last decade. System oversizing and value-engineering (*shudder*) have been all too common and poor resident experiences have led to a poor perception of heat networks. However, that has been changing over the last few years and I believe the improvements are only going to accelerate. Why am I so optimistic? In no particular order, here are six initiatives and processes that are changing the way residential heat networks are being delivered.

Heat Networks Code of Practice update (CP1.2)

CP1 was the first really powerful document that focused on improving heat network design in the UK. While it has certainly improved the status quo, I have always felt that it was too broad and sometimes didn’t go far enough. This is about to change though with the revised and updated CP1.2 which is due to be released soon. As contributors and steering committee members, FairHeat can confidently say that CP1.2 will provide much more specific design detail, including actual design and operational metrics and KPIs, and a method to assess whether heat networks are CP1.2 compliant. This is a big step forward as it is likely that CP1.2 compliance will result in a developer being able to use better SAP10/11 figures and it will also be linked to HNIP (or any government) funding. I expect that the GLA and other planning authorities will quickly make it a planning condition.

Acceptance testing

This is a full testing process of every dwelling on a heat network (not only 10% or witness only but actual testing). We have developed this process over the last five years and we’re now applying the approach in over 3,000 new-build heat network dwellings per year, a significant proportion of the market. Acceptance testing ensures that the development is operating as per design at handover. This will now be a minimum requirement in CP1.2 which will ensure more heat networks are operating as per design and closing the dreaded performance gap. Also, we’re up for the innovation award for our Acceptance Testing process at the ADE 2019 awards – wish us luck!


Based on the UK government’s response to the CMA report published in 2017,  regulation is coming very soon. It’s unclear what this will look like but it is likely to heavily relate to CP1 and the Heat Trust thereby providing residents with much greater protection. This should significantly increase transparency in the industry and provide new drivers for housing builders (both public and private) to deliver better performing heat networks. The Scottish government is leading the way at the moment and have just announced that they will be developing a heat networks bill in the next 12 months which will introduce the first heat network regulation other than metering and billing in the UK.


Back in 2015/2016, we developed an HIU testing regime with Martin Crane from Carbon Alternatives that takes HIUs through their paces. The ownership and administration has now been fully transferred to BESA, however, we still have a presence on the steering committee. The output from the tests is a report that provides clear metrics to compare performance (VWARTs) and also includes around a dozen graphs which plots several metrics allowing designers to get a clear picture of how the unit works in reality. Due to the impact of these tests, the performance of HIUs have improved significantly in the last few years. There are now 13 manufacturers with published results meaning that clients can now easily specify equipment that performs well – only specify HIUs with BESA published results as a minimum. It’s also referenced in CP1.2 which will mean that there is further drive to ensure all HIU manufacturers have their units tested.

Market maturity

There is a much better supply chain for heat networks now than even five years ago. This includes client knowledge (asking for the right stuff in detail), designer knowledge, contractor skills, commissioning skills and much better equipment installed (see BESA HIU test).

Be seen

The GLA are looking to develop KPIs in the new London Plan that can be enforced during planning. We’ve been providing input to developers working with the GLA and the GLA directly. Everyone is realising that it is a more complex issue than first imagined and it’s not entirely clear yet how these will be implemented or the mechanism for enforcement. However, it’s clearly a step in the right direction and should be applauded.