Short version? Check which fan you've got first, because EC controllers aren't universal. For most tents running a Global Air or Systemair Vector fan, the Global Air EC2 at £86.99 is the one we'd buy. It works off temperature and balances intake against extraction. Got a Rhino fan? The Rhino EC Smart Fan Controller at £90 plugs straight in. AC Infinity owners want the AC Infinity UIS Controller 69 Pro at £90.99 for app control. Just need to turn one fan down? The Global Air EC Dimmer does that for £13.99. And if you want temperature, humidity and everything else in the room on one box, that's the GAS Enviro Controller v4 at £295.
The best EC fan speed controllers
Global Air EC2 Fan Speed Controller with Balancer
Small box, does the two jobs most tents need. It speeds your fans up and down with the temperature, and it keeps extraction running ahead of intake so the smell stays inside.
- Thermostatic
- Built-in balancer
- Powered by the fan
- Active cable included
- Set a maximum and minimum speed for the outtake fan, and the intake follows it
- No power pack, so that's one less plug in a socket strip that's already full
- Works with the Hyper Fan V2 too, with a Pack 16 adapter (£5)
Rhino EC Smart Fan Controller
Your Rhino Ultra came with a little dimmer box, which is fine until the lights come on and the tent cooks. This is the upgrade. Pick a temperature and it moves the fans for you.
- Touch screen
- Temperature probe
- 1 to 100% in 1% steps
- Cable included
- 100 steps, so the speed changes are smooth rather than clunky
- Plugs straight into Rhino EC fans, no adaptors to hunt down
- Adjusts every connected fan together to hold your temperature
AC Infinity UIS Controller 69 Pro
For anyone who wants to check on the tent from the sofa. Or from Spain. WiFi and Bluetooth, four ports, and each device gets its own program.
- WiFi and Bluetooth
- 4 ports
- Temperature, humidity, VPD
- 12ft sensor probe
- Fans and lights can both react to temperature and humidity
- The app does alarms, history charts and CSV export, if you like a spreadsheet
- Set a minimum idle speed that only climbs when something triggers it
No need for WiFi? The 69A Bluetooth is £49.99. Want eight ports? The 69 Pro Plus is £139. Want the full rundown on the fan to pair it with? Read our closer look at the AC Infinity Cloudline S-Series.
View AC Infinity 69 Pro
Global Air EC Dimmer (Cable Pack 32)
If your fan's too loud at full whack and you just want it lower, this is all you need. Plug it in, turn it down, get on with your day.
- Manual speed control
- One Systemair EC fan
- Cable pack included
- Plug and play, with nothing extra to buy
- Compact, so it tucks out of the way
Rhino 2EC + RH Fan Controller
Temperature isn't always the problem. Come lights off the room cools, the air gets damp, and that's when mould starts sniffing around. This one watches humidity as well and has its own night settings.
- Temperature and humidity
- Day and night settings
- Fan balancer
- Digital interface
- Holds negative pressure to within 1% of fan speed, which stops a tent ballooning or sucking in
- Separate day and night targets, so plants get less of a shock at the changeover
GAS Enviro Controller v4
Think of it as the brains of the room. Fans, heaters, humidifiers, dehumidifiers and lights can all hang off the one box.
- Temperature and humidity
- 4 programmable sockets
- 26 amps total
- Built-in balancer
- Separate day and night settings, with a light sensor in the probe so it knows which is which
- Each socket takes up to 2,200 watts. For grow lights, keep to 2,400 watts across all four
- The probe unplugs from the outside of the unit, so swapping it isn't a faff
- Works with Systemair EC fans, Rhino Ultra EC fans and the Hyper Fan V2 with an extra cable
Shop all fan speed controllers
Which cable do you need?
This is where most orders come unstuck. You buy a lovely controller, open the box, and the plug doesn't fit your fan.
An EC fan stays plugged into the mains. The controller talks to it down a low voltage signal cable, so that cable is what has to match. Global Air use two kinds. Active cables have white connectors and all three pins wired up, which lets the controller draw its power from the fan. No extra plug needed.
- Global Air EC1, EC2 or EC5? Active cables only. One comes in the box with each of those.
- Global Air AC-EC? No cables included. Active or non-active both work, one for each fan.
- Two fans off one outlet? That's the Active Y-Splitter. Keep the intake fan a size smaller than the extraction fan to hold negative pressure.
- Phresh Hyper Fan V2 on a Global Air controller? You need the Pack 16 adapter. Note that the AC-EC won't run V1 Hyper Fans at all.
- Rhino Ultra on a Global Air controller? Use the 3 Pin Adaptor Cable (RFC-3PADAP). Lost the lead between the fan and its dimmer? That's the 3.5mm Control Cable.
The cables we get asked for most:
At a glance
Quick refresher. A dimmer holds whatever speed you set, while a thermostatic controller moves it for you. And the balancer column is about the gap between intake and extraction.
| Controller | Fans it suits | Reacts to | Balancer | Price |
|---|---|---|---|---|
 Global Air EC2 |
Systemair EC, Hyper V2 with adapter | Temperature | Yes | £86.99 |
 Rhino EC Smart |
Rhino EC only | Temperature | No | £90.00 |
 AC Infinity 69 Pro |
AC Infinity UIS, others with adaptors | Temperature, humidity, VPD | Separate programs | £90.99 |
 Global Air EC Dimmer |
One Systemair EC fan | Nothing, it's manual | No | £13.99 |
 Rhino 2EC + RH |
Rhino EC Ultra | Temperature, humidity | Yes | £142.99 |
 GAS Enviro v4 |
Systemair EC, Rhino Ultra, Hyper V2 | Temperature, humidity | Yes | £295.00 |
Prices as at November 2026. Check the product page for the live price.
How to choose
- Start with the fan. Rhino controllers want Rhino fans, AC Infinity wants UIS kit, and Global Air suits Systemair-based EC fans. Everything else is cables and adaptors.
- Just too noisy? The EC Dimmer or, on a Rhino Ultra, the box it came with.
- Temperature all over the shop? The EC2 if you run intake and extraction. The EC1 if it's just the one fan.
- Damp at lights off? You want something reading humidity. The Rhino 2EC + RH or the Enviro v4, depending on your fans.
- Still running an AC fan alongside an EC one? The Global Air AC-EC handles both at once.
- Not sure your fan's big enough to begin with? No controller fixes that. Run it through our grow room fan and filter calculator first.
Choosing the fan itself? Our grow room extraction guide takes you through it.
Quick answers
Can I use a normal fan dimmer on an EC fan?
No. A plug-in dimmer like our 300W one is made for AC fans. An EC fan stays on the mains and takes its speed from a low voltage signal cable, so it needs an EC controller.
Do EC fans need a speed controller?
Not always. Rhino Ultra fans come with a basic dimmer box as standard, so you can set a speed straight away. A proper controller earns its money when you want the fan to react to temperature or humidity on its own.
What is an active EC cable?
It's a cable with white connectors and all three pins connected, so the controller can take its power from the fan. Global Air's EC1, EC2 and EC5 only work with active cables.
Can one controller run two EC fans?
Yes, most of them can. The Global Air EC2 and EC5 take a second Active cable, the EC1 uses an Active Y-Splitter, and the Enviro v4 has a built-in balancer for intake and extraction. The EC Dimmer is the exception, as it only runs one fan.
What does a fan balancer do?
It sets the speed gap between your intake and extraction fans. Keeping extraction ahead gives you negative pressure, which stops smells escaping and stops a tent ballooning.
Will a Global Air controller work with a Rhino fan?
Yes, with the Rhino 3 Pin Adaptor Cable (RFC-3PADAP) at £6, which connects a Rhino Ultra EC fan to GAS controllers. Hyper Fan V2 owners need the Pack 16 adapter at £5.
Still stuck? Give us a ring on 020 8686 9643 or email info@thehydrobros.com.
Or pop into the shop for a natter: Unit 12, Progress Business Park, Progress Way, Croydon CR0 4XD.
More grow guides
- Grow room extraction: choosing a fan and filter
- AC Infinity Cloudline S-Series: a closer look
- Best carbon filters for grow tents
- Best clip and circulation fans
- Best dehumidifiers for grow rooms
- Best grow tents by size
The Hydro Bros Team. We sell this kit and talk growers through it every day in our Croydon shop.
