radiator
/ˈɹeɪ.diˌeɪ.tɚ/noun
A device that releases heat, such as the part of a car that cools the engine or a metal unit that warms a room.
Context picks the sense: under a car hood it cools the engine, under a window it heats the room.
Related words
thermostatA device that senses temperature changes and switches heating or cooling on or off to keep a room at a chosen setting.mantelThe shelf over a fireplace, which can also help support the chimney structure above it.furnaceA machine that produces heat to warm a building.fireplaceA recessed hearth built into a wall at the bottom of a chimney, where a fire can burn indoors.boilerA machine that heats water or another liquid so the heat can be carried through a system.skylightA window set into a roof or ceiling that lets daylight into a room.