Enough to cover 25sqm assuming 450mm joist spacing The product is a set of 53 heat spreader plates by Nuheat, designed for underfloor heating systems. These 14mm thick plates, JDPA14C , are specifically made to evenly distribute heat and provide efficient heating in a room. With the Nuheat brand known for quality and innovation in heating products, these heat spreader plates are likely to be reliable and effective in enhancing the performance of underfloor heating systems. The plates are designed to be installed on top of joists before the structural flooring is installed