Chicago Furnace Facts Your Forced Air Furnace's Role in Your Allergies A forced air furnace heats up air and then blows the heated through your heating vents and out into the rooms. Along with the warm air comes dust and tiny pollen particles that have accumulated in your ducts throughout the allergy season. At first, allergy sufferers may look forward to the winter season as a relief from their allergies and cold symptoms that have occurred during the rest of the year. While cooler Continue Reading ...