HVLS Fans: Choosing Between a Damper and a VFD Controller

Warehouses and industrial facilities can be places of uncontrollable climate change. Whether it is in the summer or during the winter, working inside an industrial set-up without proper ventilation can be challenging. HVLS (High Volume Low Speed) fans, simply referred to as “industrial fans,” are the superheroes that can provide a comfortable interior ambiance in every weather condition. To regulate the cooling and heating effects, control the energy expenses, and restrict condensation, it is necessary to utilize the right industrial fan controller and reap the benefits.

Choosing between a damper controller and a VFD

When it comes to industrial fan application and installation, multiple choices can be made. There is one simple choice that can induce a big difference in the functioning of industrial fans in the long term. Opting between a damper controller and a VFD (variable frequency drive) controller is a big decision as it helps to regulate the potential of industrial fans. Some industrial facilities and warehouses might opt for both controllers, depending on the needs and applications of the fans. On the other hand, several industrial fan users choose between the two.

What is a damper controller?

An industrial fan damper controller has a similar working mechanism to the air vents that are used in cars. One can easily open and close the fins to adjust the increase or decrease of airflow. This is executed by increasing the opening and decreasing the closing fins, and vice-versa, as and when required to regulate the weather in different weather conditions. While utilizing the industrial fan damper controller, the fan and motor speeds are constant. The industrial set-up damper controller offers two primary types, and the potential of the fan is adjusted with distinct system impacts.

1.      Inlet Vane Damper

It is installed on the intake of the industrial fan. It rotates the air in the same direction as the industrial fan swirls. They are easily controlled with electric or pneumatic mechanisms. The intel vane damper is considered one of the efficient industrial fan controller options as power consumption can be significantly curtailed.

2.      Outlet Damper

It is placed or installed on the exit opening of the industrial fan. Outlet dampers can accelerate the air while it leaves the industrial fan. This damper option is not picked by industrial establishments and warehouses because it doesn’t seem to efficiently regulate the airflow control in a given space.

What is a VFD?

VFD or Variable Frequency Drive is a motor controller that can be used to adjust the motor speed of an industrial fan. This indicates that with the help of a VFD, changing the speed of the fans is easier and more efficient. With a VFD controller, industrial set-ups can adjust the flow of air either by increasing or decreasing the speed of the fan’s motor. If one understands the analogy associated with the air vent mechanism used in cars, the functioning of the VFD controller in an industrial fan can be easily gauged. Instead of opening or closing the air vent, the VFD controller can reach over and alter the speed of the HVLS fans.

Deciding between a damper controller and a VFD controller

An industrial set-up doesn’t function well in constant temperature conditions, and several interior and exterior factors come into play. Flexibility and energy savings are two important aspects to consider when choosing between a damper controller and a VFD controller. Some vital considerations to keep into account are:

  • The number of hours the industrial fan will be operating
  • The power expense in a specific US state
  • The extent of limitation concerning the system controls

Both damper and VFD controllers play their unique roles in the requirements and demands of an industrial fan set-up in an establishment. Studies reveal that damper controllers have lower up-front expenses when compared with VFD controllers. But when it concerns long-term savings in energy expenses, VFD is a better industrial fan controller option. Furthermore, a VFD controller offers maximum system flexibility, which is vital for the optimal operation of industrial fans. Out of the two, in the majority of industrial setups, a VFD controller is the preferred option. Dampers are used to control the HVLS fan’s output. But limiting the speed of the industrial fan via VFD is a more energy-efficient procedure and achieves the same impact.

Why use a VFD to control an industrial fan?

Some benefits are:

Better airflow control

By using a VFD controller, it is easier to control the airflow of HVLS fans, based on the weather conditions. For instance, if the temperature inside a warehouse or an industrial establishment rises, the speed of the fan can be increased effortlessly, which offers a higher cooling effect inside.


Since the flow of air demanded from the industrial fan is variable, the capacity to restrict the speed of the fan decreases the consumption of power. This indicates there are energy savings. Furthermore, a VFD industrial fan controller can also restrict power consumption when the motor of the fan is initiated.

Higher durability and cost-saving

Since there is decreased power/energy consumption, the motor’s durability is higher. Furthermore, a VFD controller doesn’t need a motor starter. Hence, it also helps to make VFD a cost-effective option in the industrial set-up.

Before the advent of VFD controllers, controlling industrial fans at two different speeds was challenging.  The problem with two-speed control was that it was expensive, and the manufacturing lead times were too long. With the present modern and advanced technologies, VFD controllers are cost-effective, and also offer multiple options for operations.


Industrial fans, or HVLS fans, have a positive reputation in the industrial sector. The fans are known to render a convenient, and comfortable environment to the employees working in an uncontrolled temperature ambiance. Thanks to technologically advanced industrial fan controller systems, industrial fans can regulate highly efficient and seamless airflow. Depending on the applications of the HVLS fans, a damper controller or a VFD controller is chosen. Some facilities make use of both types of controllers, while others prefer VFD controllers over others.

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