Forced air heating systems can be fueled by gas, oil, or electricity. Air is heated in the furnace and then blown through ducts, which distribute the heated air throughout the home. In this type of home heating, a thermostat keeps track of the current room temperature and triggers the furnace to start up when the temperature drops below a certain degree. Since vents are used to distribute the air in the room, you don’t always get even heat. The area near the vent might be warm, but far away would be colder.