The Air Duct tool is used to draw the ductwork for your heating and cooling system. Air ducts are the pathways that carry warm or cool air from equipment like a furnace or air conditioner to different rooms in the house. For example, ducts connect the main unit to vents in bedrooms, living rooms, or hallways so air can flow properly.

To use the Air Duct tool, go to the HVAC tab in the main toolbar and select it. Then click and drag between vents, returns, or source components (such as a furnace) to create the duct connection. After placing a duct, you can adjust its shape by dragging the endpoints, or change its width and depth in the Properties panel. Keep in mind that air ducts are visible in the 2D view only, since they are mainly used for planning the system layout rather than visual appearance in 3D.