8 Best Inline Duct (Exhaust) Fans for Grow Tents and Grow Rooms

An inline duct fan is a mechanical ventilation device installed inside the ductwork to circulate air and maintain proper airflow. It works by drawing air through the fan and pushing it along the ducts, increasing ventilation efficiency.

Benefits of using an exhaust fan for a grow tent include improved air circulation, temperature control, and reduced humidity.

Choosing the best inline duct fan for a grow tent depends on factors such as the size of the grow tent or room, noise level, and power consumption. It’s important to consider these factors to ensure optimal performance and functionality.

1. VIVOSUN D4 4 Inch Inline Duct Ventilation Fan – Best Pick

The VIVOSUN D4 Inline Duct Ventilation Fan includes a fan speed of 2500 RPM, resulting in an airflow of 195 CFM.

It efficiently ventilates grow tents, transfers heat or cool rooms, and circulates fresh air. The fan operates quietly at 30 dB due to a flow deflector that reduces sound output. The low-noise operation does not oppose any harm to your health, nor does it disturb your work. 

Safety features include ETL listing, automatic reset to prevent overheating, and the electrical junction box flame-retardant components. The fan is easy to install with simple hookup flanges and a 5.9-foot-long cord. Cleaning and maintenance are hassle-free thanks to detachable housing, impeller, and blades. 

This fan’s versatility shines in improving airflow, reducing humidity, eliminating odors, and cooling spaces like grow rooms, basements, and kitchens. The VIVOSUN Inline Duct Ventilation Fan is a powerful, quiet, and safety-focused solution for enhancing air quality and climate control in various settings.

We rated the VIVOSUN D4 Inline Duct Ventilation Fan at 4.5/5.

Pros: Easy cleaning and maintenance.

Cons: Some users report short longevity. 

2. AC Infinity CLOUDLINE PRO S6 Inline Duct Fan – Best 10-Speed  Inline Duct Fan

The AC Infinity CLOUDLINE PRO S6 Inline Duct Fan is designed for versatile use, such as ventilating grow tents, transferring heating/cooling, circulating air, and exhaust odors.  

The AC Infinity has a wired 10-speed fan controller ranging from low to ultra-high and is compatible with UIS controllers. The PWM-controlled EC motor ensures quiet and energy-efficient performance with minimal heat and noise. 

One standout feature of this fan is its quiet operation. Thanks to a flow deflector that concentrates the fan stream and reduces turbulent kinetic energy. Moreover, it operates at just 30 dB, ensuring it won’t disrupt your work or harm your health. 

Its mixed flow design with a stator blade and hydrodynamic wind circles enables efficient airflow in high-resistance areas such as bends in the ductwork. The fan has a duct size of 6″, dimensions of 7.9 x 12.6 x 8.4 inches, and an airflow of 402 CFM. It features dual ball bearings for durability.

We rated the AC Infinity inline duct fan at 5/5.

Pros: Multiple speed control.

Cons: High price.

3. AC Infinity RAXIAL S6, Inline Booster Duct Fan – Best Quality Build

The AC Infinity RAXIAL S6 Inline Booster Duct Fan is designed to increase airflow in HVAC systems (heating, ventilation, and air conditioning) and ventilate home spaces like workshops.

The AC Infinity fan comes with a variable fan speed control that ranges from low to high speed and a low noise operation you can control with a rotating knob.

The unibody die-cast construction ensures smoother airflow by reducing vibrations. The AC brushless motor with steel blades provides reliable performance. 

However, it may not be suitable for restricted airflow applications such as bends in the filters. 

With a duct size of 6 inches, compact dimensions measuring 7.28 x 5.90 x 5.90 inches, an airflow capacity of 265 CFM, and a noise level of just 35 dBA, the RAXIAL S6 strikes a balance between power and quiet operation. However, compared to the AC Infinity Cloudline fan, the Raxial is louder.  For the noise-sensitive customers, we recommend getting the Cloudline product instead. 

The RAXIAL S6 features dual ball bearings, which can enhance the fan’s longevity and stability. This can be particularly advantageous in environments such as the grow tents where the fan runs for extended periods.

We rated the AC Infinity fan at 4.5/5 based on its durability.

Pros: Designed to increase airflow in HVAC systems.

Cons: Limited duct size of 6”.

4. TerraBloom ECMF-200 Inline Duct Fan – Best Variable Speed Fan

The TerraBloom ECMF-200 Inline Duct Fan is a versatile option for indoor grow facilities, vertical farms, heating and cooling transfer, and air filtration applications.

The Terrabloom offers a high airflow rate of 569 CFM while using only 74 Watts at max speed, resulting in an annual cost of $190 for 24/7 operation. 

The fan’s brushless EC motor and dual jet type blades ensure optimal performance without wasting electricity at lower speeds. It provides precise control with the included variable speed controller. The fan also offers the option to upgrade to a wireless remote or intelligent thermostat speed controller.

The coated steel housing protects the motor and blades, reducing maintenance needs, and it has an IPX4 ingress protection rating. The fan has an 8″ (200mm) duct diameter, operates at a noise level of 38-62 dB, and offers a pressure of 412 Pa.

The TerraBloom fan has an IPX 4 ingress protection rating( protection against the intrusion of solid objects, like dust and particles), making it more resilient to moisture and environmental factors than the VIVOSUN and AC Infinity fans, which do not have the same level of protection.

We rated the TerraBloom inline duct fan at 5/5. 

Pros: Affordable to use in prolonged periods. 

Cons: Only compatible with 8’’ duct diameter.

5. TURBRO AirSupply ES4 – Easy Installation

The TURBRO AirSupply ES4 Inline Duct Fan is a reliable option for efficient ventilation due to its high-quality construction of an airtight steel case and IP44 waterproof protection.

The AirSupply ES4 has an airflow of 195 CFM at 5000 RPM and consumes only 18 watts of power. 

Installation is hassle-free, with no additional assembly required. The permanently lubricated bearing reduces maintenance needs.

Suitable for various applications, including grow tents, greenhouses, bathrooms, server rooms, A/V equipment, and industrial workshops, it effectively enhances air circulation and removes moisture and odors. The seller offers a 2-year warranty. 

We rated the Turbro inline fan at 4.5/5.

Pros: Easy to install

Cons: It may not be suitable for high-demanding ventilation, like grow rooms.

6. VIVOHOME 4 Inch 195CFM Plastic Round Exhaust Inline Duct Fan – Best For Wide Applications

The VIVOHOME 4-Inch Plastic Round Exhaust Inline Duct Fan is an efficient and space-saving solution for various ventilation needs, such as grow tents.

With its quiet and efficient design, it excels in ventilating grow tents, transferring heat or cool air, and maintaining proper humidity and air quality. The 195 CFM airflow capacity is impressive, although it’s essential to note that this value is tested at zero atmospheric pressure.

Premium construction ensures smooth and whisper-quiet operation, with high-quality components in the blades and precise craftsmanship in the centrifuge to reduce noise and vibration. This fan operates at 2930 RPM with 195 CFM airflow while maintaining a low 30 dB noise level, ensuring minimal disruption.

Installation is hassle-free, thanks to the simple affixing of the exhaust and intake mounting flanges with locking tabs, eliminating the need for tools or screws. Cleaning and maintenance are also straightforward, with easy-to-detach housing, impeller, and blades.

The VIVOHOME fan finds wide applications in various settings, from indoor ventilation and odor filtration in grow tents to hydroponics.

We rated the Vivohome inline duct fan at 4/5.

Pros: Quiet operation. 

Cons: No speed control.

7. VEVOR Inline Duct Fan – Best Long-Lasting Inline Fan

The VEVOR Inline Duct Fan distinguishes itself with its exceptional airflow capacity of 807 CFM, making it ideal for various applications, from air-planting tents to kitchens and basements. 

This fan operates quietly at just 39 dB, ensuring it won’t disrupt your work or daily life, while its high-quality EC motor also reduces energy consumption by 30%, offering long-term cost savings.

The smart controller provides flexible control options, including ON/OFF, TIMER, and AUTO modes, with temperature and humidity-based automation and an auto alarm function. VEVOR simplifies installation by providing stainless steel clamps, non-vibration rubber mats, and straps, and it offers the choice of hanging or wall mounting, adding to its versatility. 

These advantages make the VEVOR Inline Duct Fan a powerful and efficient choice, particularly when compared to fans with lower airflow capacities, such as Turbo Air Supply.

We rated this product at 4.5/5.

Pros: Low-noise operation.

Cons: Pricy.

8. iPower 4 Inch Inline Duct Ventilation Fan – Best Quiet Operation

The iPower 4 Inch 195 CFM Inline Duct Ventilation Fan is a mini construction fan with dimensions 7.7″D x 8.1″W x 7″H  designed for a small grow room. It suits various settings such as grow tents, greenhouses, grow rooms, kitchens, bathrooms, basements, locker rooms, and garages.

This fan effectively brings air to your desired location quickly and quietly. With a fan speed of 2500 RPM, it generates an airflow of 195 CFM. The low noise design keeps the sound output as low as 30 dB.

The iPower Inline Duct Ventilation Fan includes a variable speed controller with three settings: HIGH, MED, and LOW, allowing you to adjust the fan speed to suit your needs. The package includes one 4-inch inline fan and one fan speed controller.

Installation is made easy with the removable duct ends that feature locking tabs for easy removal and maintenance. The fan features flanges on both the intake and exhaust ends, allowing for easy hookup, and comes with a 5.9 feet long power cord.

The iPower fan can improve air flow, reduce humidity, clear the air, and lower temperatures.

We rated the iPower fan at 4.5/5. 

Pros: Three-speed control settings.

Cons: Limited to a 4” duct size.

How Do You Choose the Best Exhaust Fans for Grow Tent Ventilation?

When selecting the best exhaust fans for grow tent ventilation, factors include price, CFM (cubic feet per minute), durability, eco-friendliness, and noise level.

• Price: Price is an important consideration for any purchase. Determine your budget and look for exhaust fans that offer a good balance between affordability and quality. Keep in mind that higher-priced fans may have additional features or better construction.
• CFM (Cubic Feet per Minute): CFM measures the airflow capacity of an exhaust fan. The ideal CFM value will depend on the size of your grow tent or space. As a general rule of thumb, aim for a fan that can provide at least 4-8 air exchanges per minute in your grow tent. This ensures proper ventilation and helps maintain optimal conditions for plant growth.
• Durability: Durability is crucial for an exhaust fan that will be running continuously in a grow tent environment. Look for fans made from high-quality materials such as steel that can withstand the humidity, temperature fluctuations, and potential wear and tear associated with indoor gardening.
• Eco-Friendliness: Consider the environmental impact of the exhaust fan you choose. Look for fans that are energy-efficient and consume less power. Energy Star certified fans are a great option as they meet strict efficiency standards and help reduce electricity consumption.
• Noise Level: Noise level is an important factor, especially if your grow tent is located in a space where noise could be disruptive. Look for fans specifically designed to operate quietly. Aim for fans with lower dB ratings (ideally 30-50 dB) to ensure a quieter and more comfortable growing environment.

What size inline fan for a 4×4 grow tent?

The recommended size for an inline fan in a 4×4 grow tent is a 6-inch fan with 250-400 CFM. This size and CFM are generally sufficient for providing adequate airflow and ventilation in the space.

However, it’s always important to consider factors such as the number of plants, lighting intensity, and desired airflow when choosing the appropriate fan size. 

What is the quietest inline fan?

The quietest inline fan is the iPower 4-inch Inline Duct Ventilation Fan. The iPower 4 Inch 195 CFM Inline Duct Ventilation Fan can maintain a noise output as low as 30 dB, which is considered an ideal noise level. To visualize this noise level, it’s significantly quieter than normal conversation, which typically ranges from 50-60 dB. This makes it an ideal choice for spaces where quiet operation is desired, such as bedrooms, offices, or any area where noise pollution needs to be minimized.

What are inline duct fans used for?

Inline duct fans are commonly used with HVAC systems to enhance air circulation and temperature control in residential, commercial, and industrial settings. 

In grow tents and indoor gardening setups, these fans regulate temperature, remove excess humidity, and exchange fresh air for optimal plant growth. In bathrooms, they eliminate odors and excess moisture, maintaining a healthier environment.

In commercial kitchens, inline duct fans exhaust smoke, grease, and cooking odors. Industrial settings utilize these fans for fume extraction, while attics benefit from improved air circulation and reduced heat buildup.

How to install an inline duct fan?

To install an inline duct fan, follow these 7 steps:

1. Disconnect the power to the area where you’ll be working.
2. Remove any existing vent cap on the exhaust duct.
3. Determine the installation location and cut a rectangular opening in the duct at that spot.
4. Align the inline duct fan in the cut opening, ensuring that the arrow label on the unit matches the airflow direction.
5. Use screws or provided mounting hardware to secure the fan in place.
6. Follow the manufacturer’s instructions to wire the fan correctly, ensuring all electrical connections are made properly and in compliance with safety regulations.
7. After installation, restore power and test the fan to ensure it functions correctly.

Where to install an inline duct fan?

When installing an inline duct fan, it is generally recommended to place it near the top of the grow tent or position the exhaust fan on the opposite side of the grow tent from the intake vent. This creates a cross-ventilation system, which ensures better air circulation and prevents the formation of hotspots.

Additionally, secure the fan to trusses in the attic area or use approved junction boxes for electrical connections.

Can you put 2 inline fans together?

While it is technically possible to put two inline fans together, it is not recommended. Inline fans are designed to be used individually to ensure proper airflow and ventilation.

Combining two inline fans can increase air pressure and improve airflow and ventilation in certain scenarios, such as complex duct systems. Suppose you have a particularly long or complex ducting system and find that a single inline fan doesn’t provide sufficient airflow or pressure to ventilate your grow space adequately. In that case, you can add a second inline fan in the series.

In this setup, one fan is placed in the ducting before the other fan. The first fan pulls air into the system, and the second fan pushes it further along the ducting and out of the exhaust.

Can inline fans be mounted vertically?

Yes, inline fans can be mounted vertically. Mounting an inline fan vertically has benefits such as space-saving, better airflow direction, and improved air circulation.

However, some disadvantages include limited mounting options, potential increased noise, reduced efficiency, and the risk of condensation issues. Vertical installation suits a tall, narrow grow space like a vertical indoor garden or a multi-tiered grow rack.

However, it is unsuitable if you have a standard rectangular grow tent with a horizontal layout.

How long do inline fans last?

The lifespan of inline fans can range from 3 years to 50 years or more.

Inline fans typically have a long lifespan, but the duration can vary depending on usage, maintenance, and quality.

When properly serviced and maintained, industrial inline fans can last up to 50 years. For residential use, the average lifespan of inline fans can be between 3 years to 15 years with proper maintenance. 

Do inline duct fans run all the time?

Inline duct fans can be run continuously, but whether they actually do depends on your ventilation system’s specific setup and requirements.

To optimize the operation of the inline duct fans:

• Consider Growth Stage: Adjust fan usage based on the growth stage; plants may not need constant ventilation during vegetative growth.
• Control Environment: Use timers, thermostats, and humidity controllers to activate the fan only when necessary to maintain ideal conditions.
• Odor Control: Use variable-speed fans for odor control to reduce noise and energy consumption when odor isn’t a concern.