AC Infinity CLOUDLINE is the gold standard for grow tent ventilation. Here's why — and the best alternatives at every budget.
Inline fans serve three critical functions in a grow tent: exhausting heat and humidity, creating negative pressure to prevent odor leaks, and providing CO2 replenishment. Sizing your fan correctly for your tent volume is essential — too small and heat/humidity builds up, too large and your tent may over-dry or get too cold.
Tested and recommended by our expert growers. All in stock and ships to all 50 states.
AC Infinity CLOUDLINE T6
AC Infinity
$149 / fan only
Shop AC Infinity CLOUDLINE T6 →Best grow tent fan period. Smart controller automatically adjusts speed based on your temp/humidity targets. Quieter than anything else.
AC Infinity CLOUDLINE S6
AC Infinity
$99 / fan only
Shop AC Infinity CLOUDLINE S6 →Best value inline fan. Same core motor as T6 without the smart controller. Pair with an Inkbird humidity controller.
GROW1 Inline Fan 6in
Grow1
$132 / with speed controller
Shop GROW1 Inline Fan 6in →Best budget option. Not as quiet or smart as AC Infinity, but solid performance for price-conscious growers.
Side-by-side specs at a glance.
| Fan | Size | CFM | Smart? | Noise | Price |
|---|---|---|---|---|---|
| AC Infinity CLOUDLINE T6 | 6" | 400 CFM | Yes (temp/humidity) | ~32 dB | ~$149 |
| AC Infinity CLOUDLINE S6 | 6" | 400 CFM | Manual only | ~32 dB | ~$99 |
| AC Infinity CLOUDLINE T4 | 4" | 205 CFM | Yes | ~25 dB | ~$119 |
| GROW1 Inline Fan 6in | 6" | 350 CFM | No | ~42 dB | ~$132 |
| GROW1 Inline Fan 8in | 8" | 500 CFM | No | ~45 dB | ~$270 |
AC Infinity CLOUDLINE T6 is the best 6" fan for most growers — the smart controller alone justifies the premium by eliminating the need for a separate temperature/humidity controller. The S6 is a great budget step-down if you already own a separate controller. For the most budget-friendly option, Grow1 delivers solid performance at a lower price.
What size inline fan do I need for my grow tent?
Match fan CFM to tent volume: 2x4 tent = 4" fan (205 CFM minimum). 4x4 tent = 6" fan (400 CFM). 4x8 tent = 6" fan running on high or dual 6" fans. 5x5 or larger = 8" fan. Size up if your grow room is already warm or humid.
Do I need a carbon filter with my inline fan?
For cannabis grows: absolutely yes. For vegetables and herbs: optional but recommended for fresh air. Pair a carbon filter of the same diameter as your fan. Always pull air through the filter (filter → fan → ducting → tent exit). The fan should pull, not push, through the carbon filter for maximum odor control.
How long does a carbon filter last?
Most quality carbon filters last 1-2 years of continuous use before the activated carbon becomes saturated and loses effectiveness. Signs it's time to replace: odors start getting through, even on high fan speed. Premium brands like Phresh, Can-Fan, and AC Infinity typically outlast budget filters.
Is the AC Infinity CLOUDLINE worth the price?
Overwhelmingly yes. The smart controller alone saves the cost of a separate humidity/temperature controller ($40-80). The 10-year warranty and ultra-quiet operation make it a one-time purchase rather than a replaceable commodity. It's the most recommended fan in every major growing community.