What is the primary function of a gas furnace?

The primary function of a gas furnace is to convert gas fuel into heat for residential or commercial space heating. This process begins when the gas is ignited within the furnace, producing combustion heat. This heat is then distributed throughout the space using a system of ducts or radiators, leading to a warm and comfortable indoor environment. Gas furnaces are specifically designed for this purpose, making them efficient heating solutions for homes and businesses that rely on natural gas or propane.

The other options do not align with the fundamental purpose of a gas furnace. Cooling air, filtering indoor air, and generating electricity are functions associated with other appliances or systems. A gas furnace is solely focused on the combustion of fuel to produce heat rather than acting as a cooling agent or a purifier. Understanding this core function is essential for anyone studying gas heating systems.