How do cast iron radiators work?

Cast iron radiators heat homes by circulating hot water. Usually heated by a boiler. The hot water runs through the hollow sections of the cast iron radiator, entering via the inlet pipe. Cast iron is the perfect material for a radiator due to its ability to absorb heat. Not only does cast iron absorb heat well, it retains it for much longer than metals such as steel or aluminium used in modern radiators. As such, even after the radiator has been turned off, it continues to emit continued warmth for hours after.

Cast iron radiators transfer heat into a room in two ways. Radiating direct heat warms people and surfaces, while convection heat warms the surrounding air. The warm air rises and circulates while cooler air is drawn down to the radiator to be heated in turn. As the water cools, it flows back to the boiler via the return pipe to be reheated, maintaining an efficient and continuous heating cycle.