iGrowtek 6-Inch Fan Controller Review & Tutorial

Short answer: the iGrowtek 6-inch fan I tested gave me a useful controller for the money. Its Smart mode stepped the fan down as the probe moved below the temperature target instead of jumping straight from one speed to off. The fan was powerful but loud, and I would not recommend buying an old or unverified listing today without a current manual, warranty and safety documentation.

Obsolete-model warning: this is a 2022 controller tutorial, not a recommendation for an unknown current listing. I could not verify an authoritative current iGrowtek product page for this exact fan/controller generation. Use these instructions only with the matching controller shown in the video, and use the manual supplied with your exact hardware as the final authority.

My iGrowtek fan review and controller walkthrough. English captions are available from the CC menu.

Video chapters

0:00 — Why real-use reviews matter
0:53 — Original value verdict
1:19 — Wattage and airflow
2:03 — Why I liked Smart mode
2:42 — Fan, probe and controller ports
3:20 — Display, units and manual speed
4:05 — Alarm mode
4:45 — Auto mode
5:26 — Smart mode step-down behavior
6:05 — Differential and controller lock

Timestamp links open the standard HWGrow pop-out player at the selected moment without losing your reading position.

Controller ports and basic controls

Fan ports: the tested controller had two fan connections, allowing a second compatible unit.
Probe port: the temperature probe connected at the top and belonged at canopy height, away from direct light and airflow.
Mode button: cycled through Off, On, Alarm, Auto and Smart.
Display button: toggled the display; a long press changed temperature units on my controller.
Up/down: changed the setting for the active mode.

What each mode did on my controller

On: ran continuously at one of six selected speed levels. Set the normal maximum working speed here before using Auto or Smart.

Alarm: set an emergency high-temperature threshold. When the probe reached it, my controller drove the fan to level six. That is a backup response, not a substitute for safely sized cooling and exhaust.

Auto: ran at the selected On-mode speed until the measured temperature fell below the target by the configured differential, then shut off.

Smart: stepped the fan down one level for each differential below the target, eventually turning it off. With a four-degree differential, for example, each four-degree drop reduced the speed by another level.

Differential: holding Mode + Down changed my tested controller from four degrees to two; Mode + Up restored four. Holding Mode alone locked or unlocked the controls.

Historical iGrowtek 6-inch inline fan and temperature controller — The exact controller generation demonstrated in the video.

Do not copy my old temperature numbers blindly

I ran speed 4, a 90°F alarm, a two-degree differential and a 79°F Smart target in one 4×3 setup. Those were settings for my room. A safe controller plan depends on the crop stage, light heat, room intake temperature, humidity, filter resistance and what happens if the fan or probe fails.

Place an independent thermometer/hygrometer near the canopy and compare it with the controller probe before trusting automation. Test every mode while you are present. Never use Alarm mode as permission to let a room drift toward an unsafe temperature.

My historical verdict: the controller logic was the reason I liked this iGrowtek, not the brand name. Today I would buy whichever current, documented system gives gradual minimum-speed control, reliable sensors, a suitable environment rating and accessible warranty support.

How current alternatives have changed

My comparison was to an older AC Infinity controller. AC Infinity’s current CLOUDLINE T6 page lists temperature, humidity and VPD control along with 425 CFM and current certification details. I would not let a 2022 comparison decide a 2026 purchase.

AC Infinity savings: If you buy from AC Infinity directly, use code EVYGROWS at checkout for additional savings on eligible products.

Use the state of indoor grow equipment guide to separate old hardware from current generations. The FTC’s advertising guidance is also why airflow, noise and reliability claims should be treated as claims until they are measured.

Useful ventilation tools

Current 6-inch inline fan with temperature and humidity controller

6-inch smart inline fanCompare minimum-speed behavior, sensor logic, certification and warranty.View product

Independent thermometer and hygrometer for checking an inline-fan probe

Independent temperature/RH meterCross-check the controller probe at canopy height.View product

Six-inch carbon filter for a compatible inline ventilation system

6-inch carbon filterAccount for filter and duct resistance when sizing the fan.View product

Next in your grow

Before this step: How to Set Up a Grow Tent: Complete Beginner Guide

Next step: Cannabis Temperature and Humidity Guide

Go deeper (supporter membership required): These advanced guides are for HWGrow supporters: Grow With Me Masterclass – Welcome. Become a supporter.

Want to watch this done step by step? The Grow With Me Masterclass follows one complete grow, day by day.

Affiliate disclosure: HWGrow may earn a commission from qualifying Amazon purchases at no additional cost to you. Equivalent current products can replace these links without changing the controller-testing method.

Continue with the grow-tent fan and filter installation guide. Need help choosing safe current settings? Ask HWGrow with the exact controller model, tent, filter, lights and room conditions.

Frequently asked questions

What did iGrowtek Smart mode do?

On the tested controller it lowered the fan by one speed level for each temperature differential below the target, eventually shutting off.

What was the difference between Auto and Smart?

Auto ran at the selected speed until the low threshold and then stopped. Smart stepped down gradually as the probe moved below the target.

Should I use your exact settings?

No. They described one 4×3 setup. Choose thresholds from your actual canopy conditions and verify them with an independent sensor.

Do you still recommend the iGrowtek?

Not as an unverified current purchase. The controller logic was useful, but buy only when the exact present model has a current manual, warranty and safety documentation.