How does a forced-air heating system work?
Room air is drawn into the return air ducts and proceeds to a squirlcage or “sirocco” fan. The air is then discharged into the furnace’s heat exchanger where the hot flue gases from the fire are cooled by the air and the air is warmed. This warm air is then forced through the heating supply ducts and up through the warm air registers in each room. Forced air systems can also include a humidifier, to add moisture to the air, filters to clean the air. and special filters to remove odors or ultra-violet lamps to sanitize the air.