Hydronic radiators are heating devices that use hot water to warm up a space. They are part of a hydronic heating system, where water is heated in a boiler and then circulated through pipes to the radiators. The hot water transfers heat to the metal surface of the radiator, which then radiates warmth into the room. These radiators come in various styles and sizes, making them suitable for different types of buildings. They are often more energy-efficient than traditional heating systems, as they can maintain a consistent temperature and reduce energy consumption. Hydronic radiators are commonly used in residential and commercial settings.