Fabric duct products, such as DuctSox, are often specified nowadays as a lower cost alternative to traditional metal ductwork for large spaces - such as gymnasiums, cafeterias, and convention halls - where large volumes of air need to be evenly distributed throughout. Manufacturers of fabric ductwork tout its many benefits: low installed cost, low maintenance, many color choices.

Before you decide, we recommend you weigh the benefits and cost savings against other factors, noise control in particular. Because it cannot be internally lined or externally wrapped, fabric ductwork reduced noise control options and may incur additional expense to achieve an acoustically acceptable space.

Using fabric duct may necessitate relocating the air handler further away from duct openings or inserting duct silencers into the path for noise mitigation. When a variable volume system is used, it causes fabric ductwork to inflate and deflate, resulting in a noise similar to the whooshing and snapping of a sailboat sail changing direction in the wind. In addition to the distraction of the noise, the process is visually unsettling.

While fabric duct can be an extremely useful product, it is not a universal solution. Consider the needs of your space carefully before choosing fabric over metal.