National radiator day – MARC urges installers to check radiator data
The Manufacturers’ Association of Radiators and Convectors (MARC) is using National Radiator Day on 1 November to remind the heating industry of the importance recognised testing, compliant Declarations of Performance (DoPs) and transparent heat-output claims in product literature, websites, catalogues and advertising.
Accurate heat-output figures and clear product information are essential to compliance, consumer confidence and effective heating design. Installers need to ensure that the radiators they fit carry compliant Declarations of Performance (DoPs). MARC is also reminding manufacturers, importers, distributors, wholesalers and resellers to check that their product data is accurate, properly evidenced and consistently presented.
Hydronic radiators, including steel panel, multi-column, designer radiators and towel rails, fall within the scope of BS EN 4421. Manufacturers must ensure that declared performance is supported by the relevant evidence and that a DoP is available for the product, digitally or on paper.
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. Because radiator output varies with operating temperatures, performance figures must be presented clearly and consistently.
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.
The consequences of inaccurate performance information can affect the property. If a radiator is chosen using an overstated output figure, it may be undersized for the room, leaving occupants uncomfortable, and potentially increasing energy consumption while undermining the heating system’s efficiency.
Andy Phillips, chair of MARC, said: “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.”
MARC says accurate radiator data is becoming increasingly important as the industry moves towards lower-temperature heating systems, where correct radiator sizing relies on reliable heat-loss calculations and performance information.
The association is working with the Office for Product Safety and Standards (OPSS) to promote compliance and improve transparency across the sector. Further guidance is available from MARC.
