Finding a solution to enhance airflow for a complicated ducting system, cool down a computer system, or improve ventilation in a small room can be challenging. An inline duct fan can solve that problem by replacing stale, moist, or smelly air with fresh, conditioned air in residential or industrial applications.
Various types of inline duct fans are available, so we've compiled a detailed buying guide to help in your search.
- What is an Inline Duct Fan?
- Types of Inline Duct Fans
- Key Factors to Consider
- Top Inline Duct Fan Brands
- FAQs About Inline Duct Fans
What is an Inline Duct Fan?
An inline duct fan is designed to improve airflow in a room. It is installed in your ductwork to circulate air for better ventilation and maintain humidity and temperature. It also removes pollutants, odors, and stale air from one room and replaces it with fresh air, especially in rooms with poor ventilation, like bathrooms, closets, attics, and grow rooms. As a bonus, these fans reduce the strain on your ventilation system, resulting in higher energy efficiency and lower energy bills.
Types of Inline Duct Fans
- Axial Fans: This type of fan is ideal for moving a large amount of air over a short distance and applications that require low pressure and high airflow, especially in residential ductwork. With a single propeller, these fans add exhaust ventilation in small spaces like bathrooms or kitchensâ.
- Centrifugal Fans: A centrifugal fan is the answer when high pressure is needed or for longer duct runs, including ductwork with bends, multiple inlets/outlets, and junctions. They are ideal for large subfloor ventilation systems, heat transfer systems, or large areas with more than 65 feet of ductwork. These are often found in commercial buildings or complex HVAC systemsâ.
- Mixed-Flow Fans: Combining the benefits of centrifugal and axial fans to balance pressure and airflow, these fans are versatile in configurations for long ductwork with bends and branches. They are great for medium or large-sized areas in residential or light commercial applications.
Key Factors to Consider About Inline Duct Fans
- Sizing and Duct Compatibility: The sizes of inline duct fans can vary from 4 to over 40 inches, so it's crucial to ensure that the fan you choose matches the diameter of your existing ductwork. An incompatible size can result in reduced efficiency or airflow issues.
- CFM (Cubic Feet per Minute): Larger rooms, spaces with more air pollutants (like kitchens and bathrooms), or a long duct run where the HVAC fan is not strong enough to move the air to the desired location will need a fan with higher CFMâ to maintain a steady airflow.
- Noise Level: Inline duct fans are typically installed within the building's ductwork and are usually farther from living areas for quiet operation. If noise level is a concern, look for fans with a lower decibel (dB) rating.
- Installation Requirements: In almost every situation, professional installation is required. DIY installation may result in unsafe connections, and improper installation may void the warranty.
- Speed Controls: Some inline duct fan models include or require a speed control so you can adjust the airflow depending on your needs. This is useful for grow rooms and other instances that require different ventilation rates.
- Warranty: For peace of mind, check the warranty information on each inline duct fan.
Top Inline Duct Fan Brands
AC Infinity, Fantech, and S&P are well-known for producing high-quality inline duct fansâ, among other ventilation systems.
AC Infinity
A well-known brand for hobby and professional growers alike, AC Infinity inline fans deliver reliable cooling solutions. The various CLOUDLINE series from AC Infinity supplies multiple sizes and can include a speed controller or thermostat to best suit your needs. These innovative systems are designed to quietly maintain ventilation in grow rooms, cool AV closets, exhaust odors, and transfer heating or cooling.
The CLOUDLINE T6 is a popular choice for 6-inch ducts. It features an EC-powered duct fan for quiet and efficient operation and an LCD thermal controller to program several convenient features.
Fantech
With almost 40 years of experience in the industry, Fantech inline fans are engineered for excellent control and economical energy use. They are designed for commercial and residential applications and come in various options, including interior or exterior, resin or metal, and more. They are backed by a 5-year limited warranty for your peace of mind.
The FG series, made of metal, is commonly used for attics, closets, crawlspaces, and other residential spaces. They are also available with an EC motor for added benefits. For commercial uses like agriculture, gyms, retail shops, and more, the prioAIR inline duct fans are resin fans in three sizes. The FKD Mixed Flow all-metal fan series is Fantech's most popular Inline Duct Fan type, offering high airflow where higher static pressure is needed.
S&P
Based in Florida, S&P has over 70 years of experience as a leading name for ventilation fan manufacturing. Their high-capacity systems are ideal for commercial spaces, while reliably quiet inline duct fans fit seamlessly into residential rooms.
The TD SILENT inline duct fans are impressive airflow solutions with ultra-quiet operation, and the SWF series Sidewall duct fans have high static pressure capacity for through-the-wall applications where typical inline mounting is not possible.
Inline Duct Fans FAQs
Do inline duct fans run continuously?
By default, an inline duct fan does not run continuously. You can control the fan's operation by wiring it to thermostats or switches, which gives you flexibility in managing energy usage only when you need it.
How big of an inline fan do I need?
To find the proper sizing requirements of an inline duct fan, it's important to calculate the air exchange per hour. Even for the smallest bathroom, it's recommended to pick a fan that provides at least 8 air changes per hour and a minimum of 75 CFM.
To find the air exchange rate per hour, use this formula: Volume / 7.5.
Find the volume (as length x width x height) of each bathroom to be ventilated. If venting more than one, add the volumes of each room together, i.e. length x width x height (bathroom 1) + length x width x height (bathroom 2), etc. Then, divide that volume number by 7.5 to find the required CFM airflow.
Which one is best for you: a centrifugal inline fan or an axial fan?
While all inline duct fans improve airflow and ventilation performance, there are different factors between the types to best fit your application.
An axial fan moves large volumes of air in low-pressure ducts. These fans are commonly used to cool both small and large spaces like a laundry room or bathroom or even electronic equipment and computer rooms.
A centrifugal fan works best to move a large air volume at high pressure like when you need to push air through long or restrictive duct runs with substantial pressure requirements. These fans cover larger areas, up to about 60 feet of ductwork, in either residential or light commercial rooms.
Do I Need an Inline Duct Fan?
When purchasing an inline duct fan, it's essential to pick a fan that is the correct size for the ductwork, including one that will fit in the available space. A properly sized and installed duct fan can significantly improve airflow while reducing energy costs and maintaining comfort in any environment.
Are you still trying to figure out the best inline duct fan for you? Call our team of product experts at 1-800-934-9194. We want to help you make your indoor environment comfortable and healthy.
