Do Duct Booster Fans Work?

Updated January 11, 2024

Yes, duct booster fans can improve air flow in heating and cooling systems, especially in rooms that are far from the HVAC unit.

But knowing a little more about how and why duct booster fans work can help determine if they’re the right solution for you.

Which is why in this post, we’ll dive into the mechanics, benefits, and considerations for using duct booster fans in your home or office heating and cooling system.

Let’s get started.

Reasons Why Airflow Seems Low

At some point, every person puts their hand up to a vent to make sure air is coming out of it. It’s a natural reaction, and HVAC systems are as susceptible to problems as anything else. When airflow seems insufficient, it can happen for a number of reasons. Leaky ducts are a common problem. Clogged filters and failing fans are in the mix too. Sometimes, the system is too large for the blower and central unit. In other cases, the vents are too long or complicated for a central system to work efficiently. If you have a vent that’s not performing as you’d like, you might consider a duct booster fan. Could it really work?

How Duct Fans Work

In general, duct booster fans are designed to regulate the flow of air out of vents across an HVAC system. How they do that depends on the design. At its simplest, a duct fan (also known as an inline duct fan or simply an inline fan) is a fan that is installed inside of a ventilation duct, rather than at the end point of a duct or through a wall.

Inline Duct Fans

Duct inline fans are designed to sit inside the ducts themselves. The duct inline fan will be installed near a vent that is far from the blowing unit of the system. It adds mechanical air pull to the ducts at the desired vent. This helps draw air along the entire system and reduces the problem of the majority of air exiting at the closer vents. 

When installing the fan, make sure that it is aimed so that the air blows in the desired direction. Even though an inline duct fan may be marketed as either an "exhaust" or "intake" fan, they can all actually be installed either way. Therefore, it is important to pay attention to which way it is being put in.

Register Duct Fans

A register fan is different from an in-duct fan. The register fan goes in the room where the airflow needs to be improved. It creates a pressure differential that draws more air out of the vent. It has the same net result as the inline fan, but it works through a different mechanism. A register duct fan is placed on the floor or wall vents to better direct airflow. 

Register duct fans can be a more cost effective solution, if they are appropriate for your application. Unlike inline fans that need to be installed within the duct work, the register fans can be connected to a plug in the room you are hoping to improve airflow in. One downside though is you will hear extra noise with having the fan directly in the space vs. in the ducting.

Which Duct Booster Fan is Better?

Your application will most likely determine whether an inline or register fan will be the best solution. While these fans both work to bring in fresh air, they should not be used interchangeably. For most industrial and commercial applications, an inline duct booster fan will be the best as it will fit in seamlessly with existing HVAC systems and ducting.

Where Inline Fans are Superior 

Whether you should use an inline fan or register fan depends on the system at play. Inline fans are typically better for longer and more complicated ducting systems. In commercial buildings, single blowers usually can't properly service the large, intricate systems. Inline blowers stay out of the operational space of the commercial facility, and they add airflow at any point that it is needed. This is where they are at their best — especially when ventilation is a health or safety issue.

Where Register Fans are Superior 

Register fans are typically better in smaller systems that need cheaper options. In a home or small office space, they can boost HVAC airflow without having to upgrade the entire system.

Choosing the Duct Booster Fan That’s Right for You

If a fan is picked that does not provide enough CFM or has the strength to push the air through the ducting, you will not be able to notice an improvement in airflow. You will also want to confirm the static pressure of the ducting you have. The static pressure will be impacted by how many bends are in your system, and in turn that will greatly impact the CFM rating. You will also want to find a fan that will work with the duct work you have installed or want to install. These fans are not one size fits all. Another great benefit to a duct booster fan is that they are incredibly energy efficient.

Conclusion

If you think a duct booster fan can help with your system, there are some excellent options to consider. Soler & Palau duct booster fans come in enough variety to solve many problems. Continental Fan duct booster fans are also well regarded for HVAC systems. Find the fans that are best for your system, and you can transform heating, cooling and ventilation without a major overhaul to the entire building.

FAQs

Where should a duct booster fan be placed?

Proper placement of a duct booster fan is important to feeling any of the benefits. When having an installer place your booster fan, they should make sure to place it in areas of poor airflow. Examples of this could be complicated duct runs or in rooms with poor ventilation.

Do duct booster fans run all the time?

There are many options for duct boosters that run all day, but you can also find some models that come with programmable controls so that you feel the benefits of the fan when you need to. Fans that come with a programmable control will also be more energy efficient.

What is the purpose of a booster fan?

A duct booster fan helps to make sure that airflow is traveling properly through ducting and bringing fresh air into your application. Inline duct booster fans aren’t appropriate for all spaces, but if you have duct work and want to hide any ventilation equipment you bring in, then a duct booster is the perfect solution.