A convector is a heater that warms a room by heating the air and letting that air move around — not by a red-hot bar you can see. Cool air goes in, the machine heats it, and the warm air rises or comes out through a grill. That moving of heat in air is called convection, which is why the machine has this name. You see convectors on walls or standing on the floor, in homes, offices, and hotel rooms. They are often quieter than a fan heater, though some models do have a small fan to push the air along. In everyday talk many people just say heater, or even radiator, though actually a radiator is usually the metal panel with hot water inside. Shops sometimes mix the names. Convector is the more precise, slightly technical word.