Ducting is vital to any HVAC system, as it is responsible for circulating heated or cooled air around a building.

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There are two main types of ducting available, a rectangular duct or a spiral duct. We will take a look at the latter in this short guide.

1 What is spiral ducting?

Easy to install, spiral ducting is supplied in lengths of 3 metres as standard. Spiral ducting has been designed to this length in order to fit in a standard truck and so that it can be fitted easily by one or two people.

2 Is it better than rectangular ducting?

In most cases, it is. Whilst there are a small number of applications where the rigidity of rectangular ducting makes it preferable, spiral ducting is far more prevalent, and it also requires around a third less raw material in its construction than its rectangular counterpart.

3 Is it better, even though it’s cheaper?

In addition to being a better option cost-wise, in most situations, a spiral duct will be the most preferable option. Due to the fact that it is easier to install, as well as being less likely to leak warm air, it is cost-effective and energy-efficient to run.

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4 How do parts fit together?

Each length of spiral ducting utilises female and male components to allow for easy assembly. Fittings include bends or T junctions, or any other element of a system of ducting that isn’t the duct itself.

5 And joining together pieces is easy?

Absolutely, as the parts of ducting have male or female ends, you will need to purchase the appropriate connecting parts in order to join them. Joining together two male ends requires a female connector, and vice versa for two female ends. The only variable here is the diameter of your ducting, but as this comes in a range of standard sizes, it should not cause any issues.

6 What about sealing the ducting?

When fastening the ducting together, it is recommended that you use self drilling screws. Then seal the joins using duct sealant, which can be applied using a mastic gun. Sealants should provide a permanent seal, allowing for movement which takes place due to vibration.