Government Regulators Crack Down on False Radiator Claims: Why MARC’s Compliance Campaign is a Win for Clean Heat 🌡️

• Patrons & Preamble: New Guild Patrons and Industry Stance.

• OPSS Takes Radiator Accuracy Seriously: The government regulator's involvement and official support for MARC.

• The Deception of Over-Claimed Radiator Outputs: The problem of Delta T60 and the serious consequences for engineers and consumers.

• Legal Compliance: MARC’s Stance: Mandatory standards (BS-EN 442, Delta T50, Delta T30) and the Declaration of Performance (DoP).

• The Humble Radiator: A Masterclass in Heat Science: Why the radiator is the perfect tool to understand heat science.

With National Radiator Day today, the timing is perfect to celebrate the essential work being done in this often-underappreciated corner of the heating sector.

I'm delighted to introduce UK Radiators as a new Patron to the Guild of Master Heat Engineers, joining Castrads (also a Guild Patron). While I'm lucky to have a small group of Patrons supporting BetaTeach and Guild engineers, it’s a point of pride that two of them are from the radiator sector. UK Radiators and Castrads are arguably competitors, but they have become good friends through mutual collaboration for the common cause of promoting good information.

You can watch me interview Rob Nezard from UK Radiators along with Nick Baylis from Castrads in the video linked here, where we discuss the crucial work MARC and its members have been doing to clean up the radiator sector.

The Manufacturers’ Association of Radiators and Convectors (MARC)—a division of the HHIC and part of the EUA—has been fighting a critical battle to uphold standards. If you’ve followed this sector, you will know the EUA often gets criticised for its push for hydrogen boilers. If you follow me closely, you’ll also know I can be critical of the HHIC and other associations (not the people within it). MARC itself declined to participate in this video once they understood I was involved—a price I pay for being quite outspoken. But I'm happy to report that in this case, MARC is doing excellent work. The industry needs disruptors like myself, as it’s clearly not where it needs to be.

OPSS Takes Radiator Accuracy Seriously: The Government is Watching

Crucially, MARC is now working closely with the Office for Product Safety and Standards (OPSS), the National Regulator for construction products, enforcing the Construction Product Regulations. This level of government involvement is a significant development, and it validates the nearly nine-year campaign for transparency and accurate performance claims across the sector.

Duncan Johnson, Deputy Director of Construction Products Regulation for OPSS, has publicly expressed his support: "We are delighted to be working with MARC to address the challenges being faced in the radiator industry, helping to ensure that manufacturers and suppliers are providing information that is both accurate and compliant with the standard."

The Deception of Over-Claimed Radiator Outputs

MARC is addressing a serious, long-standing problem: some manufacturers and retailers are selling radiators with exaggerated heating claims, leading to overstated heat outputs. This arises because some suppliers are declaring output at Delta T 60 or higher.

This is serious. If engineers are diligently designing heating systems and have calculated the estimated heat loss a room will need, it’s deeply concerning if the radiators they then purchase cannot deliver the heat they claim.

Using non-compliant Delta T60 values misleads consumers and results in incorrectly undersized radiators. This can lead to:

• Colder homes and higher energy bills because the heating system has to use higher flow temperatures to stay warm.

• A risk of increased carbon emissions, which directly conflicts with net-zero targets.

• Wasted Public Money: This is especially important for BUS-funded heat pump systems. If a heat pump is installed with radiators that don't match the reported manufacturer claims on heat output, the heat pump may appear to underperform when the real issue is incorrect radiator sizing.

Legal Compliance: MARC’s Stance

MARC is reminding all radiator suppliers—including manufacturers, distributors, wholesalers, and resellers—that they have important legal obligations under the Construction Products Regulation 2011.

• Compliance is Mandatory: Hydronic radiators are covered by the designated standard BS-EN 442.

• Declaration of Performance (DoP): All radiators must be supplied with a Declaration of Performance which is a legal requirement. This document confirms the product has been tested by an independent laboratory and that the declared heat outputs are accurate.

• Standardised Output: The heat output must be declared at Delta T 50 for standard heating systems and Delta T 30 for low-temperature systems. Andy Phillips, Chair of MARC, emphasised that using Delta T60 or higher values is in breach of the Regulation.

The OPSS involvement means businesses failing to comply with these requirements are now at risk of regulatory investigation, validating the necessary work MARC has been doing.

Thanks to the Patrons

The Guild of Master Heat Engineers is supported by our Patrons.

Learn more about our Patrons here.

The Humble Radiator: A Masterclass in Heat Science

I am very lucky to have two radiator companies as Guild Patrons because the topic of radiators can help us all understand domestic central heating.

Why is the topic of radiators so important to me?

Radiators are simple things. Nearly everyone recognises these innocuous components of our heating systems. The reason I like this particular sector of the heating industry—heat emitters—and why I'm happy to have radiator Guild Patrons is because we can use the radiator to help people understand the science of heat: how it moves into and out of a building.

• Heat is Speed: We have all heard the term Watts and Kilowatts (kW), but what is perhaps little known is that this means the speed at which heat is moving. 1kW in reference to heat literally means 1 kilojoule (1,000 Joules) of heat is moving every second. Where is it moving? It’s moving to a colder temperature. So in winter, the heat inside homes moves outside. Always. Even with good insulation, it still moves outside. You can’t stop it; you can only slow it down.

• Dynamic Control: It is the radiator which moves heat into buildings, and we can control the speed at which it moves into the building to match the speed heat is leaving the building. We do this by changing the flow temperature to the radiators, a capability which boilers have possessed for many, many years, but which the sector as a whole was never concerned with promoting. Arguably, the boiler manufacturer Viessmann did its best in trying.

Flow temperature to radiators should be dynamic—that is, changing to what is needed. Unfortunately, our controls industry has been quite rubbish at elucidating that point up until recently. Many boiler engineers, even the great ones who are very capable of getting your boiler going again in the cold, are unaware of the science around heat. It’s not totally their fault, as the heating sector tends to bombard them with marketing rather than science and best practices. Many of these engineers think radiators need to be hot. What they actually need is different flow temperatures at different times.

This lack of dynamic control was a huge missed opportunity for the sector, particularly since 2 million HIVE thermostats in homes use a fixed flow temperature. This means the speed of heat entering the home is nearly always way off. This fixed, higher flow temperature required by the Hive system and others prevents dynamic control and can lead to the boiler constantly cycling on and off, which reduces its longevity. Furthermore, this consistently high flow temperature increases the rates of corrosion to components like radiators. The loss of data from these 2 million homes, which could have been collected had the system offered dynamic control from the start, is an unprecedented missed opportunity for the heating sector.

I’ve been chatting to Hive for years, pushing for them to place a control on the market which can do dynamic flow temperature, and they finally listened—their latest model can now do this. Unfortunately, despite this innovation, their latest marketing campaign involving a loyalty scheme with installers still incentivises their old, non-dynamic thermostat.

The company still needs to go further. I'll soon be doing an article about HIVE thermostats where we will be discussing how they could turn things around and take a leadership role with some honest messaging.

The humble radiator doesn't have moving parts. It’s simple. And the manufacturers in the association don't have to come up with silly USPs. We can not only learn a bit of the science from the humble radiator, but it’s a niche sector which other parts of the heating sector can look at and take examples from—particularly in their commitment to honest, accurate reporting of their product's outputs.

Watch the video linked here to hear more about MARC's campaign.

Have a great week everyone.

Nathan

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