Ventilation|Updated 2025-01-01

Best Inline Fans for Grow Tents in 2025

Quiet, powerful ventilation for healthy plants and odor control

Jump to:#1 AC#2 AC#3 VIVOSUN

Good airflow is critical for cannabis health - it prevents mold, strengthens stems, and works with your carbon filter to control odor. We tested the top inline fans to find the best for home grows.

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#1Editor's Choice

AC Infinity CLOUDLINE T4

Best Overall for Home Grows

$109.99
(4.8)
AC Infinity CLOUDLINE T4

Our Verdict

The gold standard for grow tent ventilation. Whisper quiet, smart controller, and perfect for 2x4 or smaller tents. Set it and forget it.

Best For: 2x2 to 3x3 tents or supplemental 4x4 ventilation
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Pros

  • +Whisper quiet operation
  • +Temperature/humidity automation
  • +PWM speed control
  • +Mixed-flow design
  • +Excellent build quality

Cons

  • -Premium price
  • -Controller could be simpler
  • -4" may be small for 4x4+

Key Specifications

Size4 inch
CFM205 CFM max
Noise25 dB at low
ControlDigital thermostat
Power30W
#2Best for 4x4

AC Infinity CLOUDLINE T6

Best for Larger Tents

$159.99
(4.8)
AC Infinity CLOUDLINE T6

Our Verdict

Same quality as the T4 but sized for bigger grows. The 6" fan handles 4x4 tents easily and has headroom for expansion.

Best For: 4x4 tents and larger grows
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Pros

  • +Handles larger spaces
  • +App control available
  • +Very quiet for its power
  • +Same great controller
  • +Future-proof choice

Cons

  • -Higher price
  • -Overkill for small tents
  • -Larger footprint

Key Specifications

Size6 inch
CFM402 CFM max
Noise32 dB at low
ControlDigital + Bluetooth
Power40W
#3Budget Pick

VIVOSUN 4" Inline Fan

Best Budget Option

$29.99
(4.4)
VIVOSUN 4" Inline Fan

Our Verdict

A solid budget choice that gets the job done. Louder than AC Infinity but effective. Good starter fan if budget is tight.

Best For: Budget-conscious beginners
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Pros

  • +Very affordable
  • +Reliable performance
  • +Easy installation
  • +Good airflow
  • +Simple operation

Cons

  • -Noticeable noise
  • -No speed control (without addon)
  • -Basic construction

Key Specifications

Size4 inch
CFM190 CFM
Noise45 dB
ControlOn/off
Power25W

Inline Fan Buying Guide

Sizing Your Fan

Calculate tent volume (LxWxH in cubic feet). Your fan should exchange that volume at least once per minute. For a 2x4x5 tent (40 cu ft), a 200 CFM fan is plenty with room for carbon filter restriction.

Why AC Infinity Dominates

Mixed-flow fan design is quieter and more efficient than old axial fans. The smart controller automates temperature/humidity. It's worth the premium for the silence alone.

Carbon Filter Compatibility

Your carbon filter reduces effective CFM by 20-30%. If your filter is rated for 200 CFM, pair it with a 200+ CFM fan to ensure adequate airflow.

Frequently Asked Questions

Do I need an intake fan too?
Usually no. Passive intake works fine for most tents - just open the lower vents. Negative pressure (exhaust only) helps with odor control by keeping all air flowing through your carbon filter.
How loud is a grow tent fan?
Budget fans: 40-50 dB (noticeable). AC Infinity on low: 25 dB (barely audible). On high, even quality fans get noticeable. Most tents don't need max speed.
Can I run my fan 24/7?
Yes, and you should. Constant airflow prevents mold and keeps odor controlled. Quality fans are designed for continuous operation. Use a speed controller to reduce it at night if noise matters.

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