The answer to 'what is furnace' is a heating appliance that is used to warm the air in a home or building. A furnace is typically fueled by natural gas, propane, or electricity, and it works by heating air that is then distributed through a system of ducts and vents throughout the building. Furnaces are an essential part of a home's HVAC (heating, ventilation, and air conditioning) system, and they play a crucial role in keeping a home or building comfortable and warm during the colder months of the year.
Furnaces come in a variety of sizes and efficiency ratings, and they can be installed in different locations within a building, such as in the basement, attic, or even closet. They are designed to be energy-efficient and to provide consistent and reliable heating, and they are an important investment for homeowners who want to ensure that their home is comfortable and well-heated.