National Radiator Day is on 1 November, and the Manufacturers’ Association of Radiators and Convectors (MARC) is reminding everyone to ‘check the radiator data’.
MARC is highlighting the importance of recognised testing, compliant Declarations of Performance (DoPs) and transparent heat-output claims across product literature, websites, catalogues and advertising.
Accurate heat-output figures and clear product information are essential to compliance, consumer confidence and effective heating design. So, MARC is urging radiator manufacturers, importers, distributors, wholesalers and resellers to check that their product data is accurate, properly evidenced and consistently presented. Installers also need to ensure that the radiators they are fitting carry compliant Declarations of Performance (DoPs).
Hydronic radiators, including steel panel, multicolumn, designer radiators and towel rails, fall within the scope of BS EN 442. Manufacturers must ensure that declared performance is supported by the relevant evidence and that a DOP is available for the product, either digitally or in paper form.
Heat output should be declared in watts at both Delta T 50 (ΔT50) and Delta T 30 (ΔT30), supported by appropriate test evidence. These figures provide a consistent basis for comparing radiator performance and calculating the heat required to warm a room.
Delta T refers to the difference between the average water temperature in a radiator and the surrounding room temperature. As radiator output varies with operating temperatures, it is essential that performance figures are presented clearly and on a consistent basis.
MARC is particularly concerned about the use of Delta T 60 (ΔT60) or higher figures in place of the recognised ΔT50 and ΔT30 values. Although a radiator produces more heat at a greater temperature difference, presenting a higher figure without clear context can give customers a misleading impression of the output they can expect.
Andy Phillips, Chair of MARC, says: “National Radiator Day is an opportunity to remind the industry that accurate product data matters. Manufacturers and suppliers should check that their heat-output claims are supported by the appropriate test evidence, that their Declarations of Performance contain the relevant information, and that figures are consistent across all their sales and marketing channels.
“Clear, reliable information helps customers compare products fairly, enables installers to make informed choices and supports confidence in our industry.”
The consequences of inaccurate performance information can affect the household for whom it is chosen. If a radiator is selected using an overstated output figure, it may be undersized for the room in which it is installed. This can leave occupants uncomfortable, increase energy consumption and undermine the efficient operation of a heating system.
Accurate radiator data is particularly important as the industry supports the transition to lower-temperature heating systems, including heat pumps. Correct radiator selection depends on reliable room heat-loss calculations and an understanding of the output available at the system’s intended operating temperatures.
MARC is working with the Office for Product Safety and Standards (OPSS) to promote compliance and improve transparency across the sector.
Duncan Johnson, Deputy Director of Construction Products Regulation at OPSS, has expressed support for this work, saying: “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.”
For National Radiator Day, MARC is encouraging businesses throughout the supply chain to review their product information, verify declared heat outputs against the relevant evidence, and ensure that technical data and advertising claims are clear and consistent.
The message is simple: check your radiator data. Accurate information supports better decisions, better heating performance and greater consumer confidence.
For further information, visit MARC’s guidance on the legal requirements for radiators.
