A furnace is a device used to generate heat, often for warming buildings or for industrial processes. It works by burning fuel, such as natural gas or oil, to produce hot air or steam. This heat is then distributed throughout a space, keeping it comfortable during cold weather. In addition to heating homes, furnaces are also essential in various industries, like metalworking, where they melt metals for shaping. The heat produced can reach very high temperatures, making furnaces crucial for tasks that require intense heat, such as in the production of steel or glass.