A furnace is a type of equipment used to heat a space or a building. It works by burning fuel, such as natural gas, oil, or wood, to generate heat. The heat is then circulated throughout the building or space via air ducts, radiators, or other means. Furnaces are often used in homes and businesses to provide warmth during the winter months. They can also be used to heat water for hot water tanks or to provide hot air for ventilation systems. Furnaces are typically installed in basements, attics, or garages, and are connected to the home’s electrical system. The efficiency of a furnace is determined by its AFUE (Annual Fuel Utilization Efficiency) rating, which is a measure of how much of the fuel is converted into usable heat. Furnaces are an important part of any home or business, and should be regularly maintained to ensure they are working properly and efficiently.