How Do Radiator Heaters Work? Radiators draw heat from water or steam and use that heat to warm up surrounding air. By doing this they can effectively be used to heat up a room. Radiators are made from metal because it’s an excellent conductor of heat. Hot water or steam travels through the radiator and the exterior fins naturally heat up over time. As those fins heat up, the surrounding air heats up as well. Radiators are one of the oldest and most effective ways of heating a home. They’re still used in buildings all over the world today and there are only a few options more effective being relied on. Radiators are still desirable because of their simplicity and their ability to heat a space evenly and comfortably. In order to get the most out of your radiator heating system, or decide if radiators are the right option for you, it’s important to understand how they work