What are the Different Types of Commercial HVAC Ducts?

Commercial enterprises that are installing, upgrading, or replacing their HVAC systems face a number of complex choices. From the brand name of the HVAC system to the sizing of the equipment, it is important to choose carefully so that your heating and cooling is consistent, efficient, and effective. When you and your HVAC professional are making decisions about your new system, take the time to give some extra consideration to the commercial HVAC ducts you’ll use for the project. The following is a brief explanation of ductwork and a description of the type of commercial HVAC ducts available.

Why Be Concerned With Ducts?

The ductwork in your HVAC system makes up the critical connection between the equipment that produces heated and cooled air and the internal spaces in your commercial facility. After your furnace, boiler, air conditioner, or heat pump generates heated or cooled air, it is directed by powerful fans into the ductwork. The air travels the length of the ductwork and exits at vents, entering your indoor spaces and providing heating or cooling. Without ductwork, there would be no pathway for the conditioned air to travel from your HVAC unit to the inside of your building.

Commercial HVAC ducts must also be properly sealed and insulated to prevent air loss at the connections. This air loss can significantly increase your monthly expenses if heated and cooled air is lost. Some types of ducts also need to be insulated to reduce the possibility of heated air cooling off, or cool air warming up, as the air travels through the duct system.

Types of Commercial HVAC Ducts

• Stainless steel — Stainless steel ducts are very common in commercial applications. These ducts are constructed of shaped stainless steel sheets and are usually either round or rectangular. Stainless steel ducts are installed in large sections, with smaller sections making up the elbow joints where the duct must bend. Sometimes the elbow joints are adjustable, allowing for relatively precise angles. Sections of ductwork must be fitted together tightly to provide stability and sturdiness and prevent air leaks at the connections. Stainless steel ducts should also be sealed at the connections with mastic, a rubbery sealant intended especially for ducts, or with metal tape. Standard duct tape should not be used for this type of sealing since the adhesive on the tape can dry out over time, breaking the seal.
• Flexible non-metallic — Flexible non-metallic ducts are made of a continuous length of metal spring sheathed in plastic or similar nonmetallic substance. These types of ducts are very light and are easy to bend into whatever shape or pattern is needed. They are useful in areas where larger ductwork isn’t practical, where space is limited, or where the ducts need to be able to follow an unusual pattern or be threaded around obstacles. Air leaks along the length of this type of ductwork are rare, but care should be taken to ensure these ducts are attached at vents and registers, where leaks are more common. The plastic sheathing covering the wire framework is also easier to puncture or tear than sheet metal ducts.
• Fiberglass duct board — Fiberglass duct board is made of compressed fiberglass with an external foil layer that resists moisture and provides an air barrier. They will have a smooth interior that offers limited airflow resistance. They are frequently lined to prevent any fragments of fiberglass from coming loose. This type of duct material is often used in trunk-and-branch duct design, forming the larger trunk lines that direct airflow into smaller branches. Fiberglass duct board is among the least costly of commercial HVAC ducts.

Our goal is to help educate our customers about Plumbing, HVACR, Fire Protection, and Alarm Systems in Mechanical, Commercial, and Residential settings. For more information on the types of commercial HVAC ducts available for your HVAC installation or replacement project, and to view projects we’ve worked on, visit our website!

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