What are the differences between spiral and regular ductwork?

As we all know, ducts move air around buildings; however, how many of us know the difference between spiral and rectangular ductwork, and whether one is better than the other?

Image Credit

According to Buildings magazine, exposed spiral ducting is a key architectural design element; in other words, it looks trendy in a contemporary design if it is exposed as a feature.

Apart from looking nice in hipster hangouts, can spiral ducting hold its own in terms of efficiency and performance?

Apart from looks, which is best?

Spiral ducts, which are also known as round ducts, can be made of very much the same materials as conventional square ducts – galvanised steel, aluminium, fibreglass board, or flexible plastic composite. Rectangular ducts use a lot more sheet metal than spiral ducts, however; in fact, the estimate is that a conventional square duct uses about one-third more metal.

Image Credit

While spiral ductwork may be economical in terms of its material use, it does not have the same economical properties when it comes to space. It definitely takes up more space than rectangular ducting.

Nonetheless, rectangular ducts have a lot of advantages in that they can be adapted to any height of building, they can be nested inside each other for economical transportation, and the flat surfaces are very convenient when a ‘trunk and branch’ design is being used because it is easier to bring in branch pipes.

Spiral ducting is undoubtedly quicker to install, and also wins out in the leakiness stakes. Many building owners maintain that the round spiral duct from suppliers such as https://www.dustspares.co.uk/ductwork-parts/galvanised-steel-spiral-duct.html is less leaky than the rectangular duct. This is because there are a lot of longitudinal joints in the latter, particularly with a long straight run of duct.

Spiral produces less rattle and shake

Noise is a major problem with many HVAC systems. As round duct is more rigid, it vibrates less than rectangular duct, which can transmit rattling and other noises if it is not properly fixed and supported. In many applications this will be the winning criteria, with noise transmission a big problem in many workplaces.

The debate over which is better is ongoing. It depends a great deal on the particular job as to which a contractor will recommend and use.