A furnace is a device used to heat a building or space. It works by burning fuel, such as natural gas or oil, to create warmth. The heat produced is then distributed throughout the home via ducts or pipes, making it comfortable during cold weather. Many people rely on furnaces to keep their homes cozy in winter. In addition to heating homes, furnaces are also used in industrial settings for processes like metalworking. For example, a blast furnace is used to smelt iron ore into iron. Overall, furnaces play a crucial role in both residential and industrial heating needs.