10 Best Quiet Inline Fans 2025 in the United States

The AC Infinity CLOUDLINE PRO S6 is a 6-inch inline duct fan designed for various ventilation needs, including grow tents, room heating/cooling, and odor exhaust. It boasts an impressive airflow rate of 402 CFM, making it highly effective in moving air through high resistance areas, thanks to its mixed flow design with stator blades and hydrodynamic wind circles. With a noise level of only 32 dB, it operates quietly, which is ideal for indoor use where minimal noise is desired.

The fan is also energy-efficient, featuring a PWM-controlled EC motor that uses only 38 watts of power, reducing your energy consumption while maintaining performance. The included 10-speed fan controller allows for precise speed adjustments, and it is also compatible with UIS controllers that offer more advanced programming options. The fan's build quality is robust, with dual ball bearings ensuring durability, and it is water-resistant, adding to its versatility.

The size and duct compatibility are well-suited for standard 6-inch duct systems, and its compact dimensions (7.9 x 12.6 x 8.4 inches) make it easy to install in various settings. However, it is worth noting that the fan is not cordless and requires a power source, and the plastic blade material may not be as durable as metal alternatives over long-term use. This inline fan is a strong contender for anyone needing a quiet, efficient, and versatile ventilation solution.

The AC Infinity CLOUDLINE PRO T4 is a versatile 4” inline duct fan designed for various ventilation needs such as hydroponic grow rooms, heating/cooling transfer, and odor exhaust. It offers an impressive airflow of 205 CFM, which should be adequate for small to medium-sized spaces. One of its standout features is its quiet operation at just 28 dB, making it suitable for indoor use without causing significant noise disturbance.

This fan is also energy-efficient, thanks to its PWM-controlled EC-motor, which helps in maintaining a low energy consumption of 21 watts. The inclusion of dynamic temperature and humidity programming, along with WiFi app control, allows for advanced automation and monitoring, adding convenience and flexibility to its operation. The fan's build quality is reliable, with dual ball bearings that enhance its durability.

However, with a duct size of 4 inches, it might not be compatible with larger ducting systems, which could limit its use in larger installations. Also, while the app offers advanced control, users who are not tech-savvy may find it a bit challenging to navigate initially. Nonetheless, for those looking for a quiet, efficient, and highly customizable inline fan, the CLOUDLINE PRO T4 is a strong contender.