The answer to 'how does furnace work' is that a furnace is a central heating system that generates and distributes warm air throughout a home. Furnaces work by using a fuel source, such as natural gas, propane, or electricity, to heat air that is then circulated through a network of ducts and vents. The basic components of a furnace include a burner, heat exchanger, blower, and thermostat.
When the thermostat senses that the temperature in the home has dropped below a set point, it signals the furnace to turn on. The burner ignites the fuel, which heats the air passing over the heat exchanger. The blower then pushes the warm air through the ductwork and out into the rooms of the home. This cycle continues until the desired temperature is reached, at which point the thermostat signals the furnace to shut off.