Furnace
Furnace (noun) /ˈfɜː.nɪs/ US /ˈfɝː-/
1. a large container for a huge fire that is heated at a high temperature to melt and burn metal and other substances – boiler:
It’s time we changed the furnace of this steel factory as it’s been overused.
2. a piece of equipment that is specifically used to heat a building and make it warm – heater:
You can sit next to the furnace if you’re cold.