Commercial Air Ducts Installation & Repair Services

How Does a Duct System Work?

Recall that a basic component of any central heating or cooling system is the blower fan, which helps to circulate air through a space. In its simplest form, ducts convey conditioned air pushed by the blower through the system, with vents attached along the way to allow the air to enter rooms. This is most often called the supply, as it supplies your business with comfortable air to moderate the temperature.

There is another set of ducts as well, called The Return. True to its name, return vents and ducts enable the system to draw back in the air that has warmed up or cooled down again for re-treatment and circulation back into the system. Return ducts also serve to assist in maintaining an even pressure gradient across the entire system, which is essential for avoiding high-pressure air leaks in ducts which can lead to decreases in efficiency and spikes in energy usage.

Larger and more complex systems may feature exhaust setups in the return, continually pulling in fresh outside air and only using return air when necessary. In some types of ducting systems, described below, a box known as the “plenum” is attached to the supply output. Plenums allow for cooler air to accumulate and help to the appropriate amount of air pressure for movement through the vents, but they also have another purpose.

Think of the plenum as a “holding tank” that helps to distribute air through a building. Without a plenum, it would be impossible to ensure an appropriate volume of airflow through every duct. Simply connecting one duct to the output and using that as a branching point would create irregular airflow. The shape and layout of the plenum therefore plays a critical role in a ducting system’s effectiveness.

Why is Duct Shape Important?

Have you ever looked at ducting? You’ve probably seen different shapes and sizes, from boxy and rectangular conduits to flexible circular tubing. There is actually a good reason for the variation. First: different shapes are necessary for carrying air to different places in a building when the structure does not allow for a straight-line path to vents.

These shapes are also more accommodating for interior duct equipment, such as turning vanes and dampers. For example, rectangular ducts made from sheet metal are more suited for housing these parts and for fitting into tight spaces in ceilings and behind walls. Spiral ductwork is easier to use for more gentle turning transitions.

Duct shape matters for energy efficiency too, however. Spiral ductwork can transport the air most efficiently and with fewer leaks owing to its unique construction. Rather than using sheet metal formed into rectangles, spiral ductwork comes in circular or oval shapes with characteristic “spiral” locks that help create an airtight seal inside the duct.

Rectangular and square ducts do not have the same ability to conduct large volumes of air to the same level of efficiency and are more prone to leaks. Most systems are a combination of the two, balanced by professional HVAC contractors to provide the correct system pressure while minimizing leakage.

The Types of Duct Systems

There is no such thing as a “one size fits all” solution for air ducts, especially considering the diversity in commercial buildings. A small café may have a duct system more akin to a residential solution, while a large, multi-story office building will have a much more complex network of conduits running throughout the building. Your contractors will choose a design based on main types of ducting systems one of the some of which are:

A series of ducts that radiate outward from a single central plenum, ideal for spaces where a single unit can reach the entire area without too much loss of pressure or velocity. More common in residential applications, but some small-scale commercial uses are viable also.

Which system is right for your building is best discussed with a professional. The shape of these systems can also have an impact on the way you approach air duct cleaning for your business, as some may be more complex to clean than others.

How can Ducts Create Different Zones?

Because ducting runs throughout your building, it is responsible for controlling the climate in many different spaces. In some larger buildings, a single unit is not enough to supply the entire space with cool air, and multiple systems with their own ductwork will be necessary instead. Climate zones, or areas that can be heated and cooled separately from one another are much easier to create when using separate systems like this. However, does that mean that you can’t enjoy the benefits of a zoned system without investing a large sum in a complex, multi-unit system?

No. As a matter of fact, there are several ways to approach zoning, from adding ducts to using items called dampers to create zones supplied from the same central air handler. Read on below for more information about how duct zones work and how they can provide benefits for your business.

What about maintenance? For the most part, your ducts won’t need much unless your technician detects a problematic leak. Leaking can happen when aluminum sealing tape wears out, or when a portion of the ductwork suffers damage somehow. While all ductwork eventually does need replacement, most systems do not need to be replaced all at once. Periodic inspections and maintenance will instead prove sufficient for identifying when action is necessary.

Dust Mites

Dust mites are tiny insects that feed off things such as the tiny flakes of dead skin found in airborne dust, and they exist almost everywhere. Can you imagine one place where there is never a shortage of dust for these tiny bugs to feast upon? If you guessed the ducts, you’re right – and dust mites, along with the dust itself, can negatively impact occupant health because their waste products trigger allergic reactions.