UNDERSTANDING THE VARIOUS TYPES OF DUCTSThe system of ductwork in your home is divided into two separate halves and typically incorporates different types of ducts. When it functions properly, the system disperses the correct volume of conditioned air to every room to maintain comfort, no matter how far the room may be located from the central unit.

Types of Ducts

Supply ducts convey heated or cooled air into rooms. The return ducts remove air from rooms and circulate it back to the furnace or air conditioner to be reheated or cooled. With airflow moving in a continuous loop, a properly balanced system delivers and removes an equal volume of air in cubic feet per minute from each room. This is known as neutral air balance, the optimum state for efficient and effective heating and cooling.

The main supply duct, known as the trunk, carries a high volume of air and is usually comprised of rectangular-shaped sheet metal ducts. Similarly, the return ducts that convey an equal volume of air back to the central unit are also usually rectangular sheet metal.

Branch ducts split off from the main trunk duct and deliver air to individual rooms. Branches are smaller diameter sheet metal ducts and usually round in shape. Dampers that can be opened and closed adjust the volume of airflow in each branch to the size of the individual room. Where the branch duct must be routed around many obstructions, flexible duct is often utilized.

When Good Ducts Go Bad

The main weakness of all types of ducts is air leakage. Over time, ductwork begins to leak conditioned air into zones like the attic, crawl space or inside of walls. The U.S. Department of Energy estimates that ducts in the average house leaks about 20 percent of the heated or cooled air it conveys. A qualified HVAC contractor can inspect and pressure-test ductwork to determine the extent and location of leaks, then offer options for sealing to restore efficiency.

For more about maintenance and repair of the various types of ducts installed in your home, contact Jackson & Sons.

Our goal is to help educate our customers in Eastern North Carolina (including Wayne, Johnston, Greene, Lenoir, Pitt and Duplin Counties) about energy and home comfort issues (specific to HVAC systems).

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