Short version? The AC Infinity Cloudline S-Series is the quiet EC inline fan we'd put on most tents and small rooms. The 4 inch S4 is £81.99, the 6 inch S6 is £97.99, and the speed controller comes in the box, so there's no dimmer to buy on top. AC Infinity rate the S4 at 28 dBA. Need a carbon filter and ducting as well? Our Cloudline Pro S extraction kit works out between £3.99 and £32.00 cheaper than buying the fan, filter and duct separately, depending on the size.
AC Infinity Cloudline S-Series
- EC motor
- PWM speed controller included
- 4" to 12"
- 348 to 2,725 m³/h
- IP44
- UK plug
The numbers
| Sizes | 4" (S4), 6" (S6), 8" (S8), 10" (S10) and 12" (S12) |
| Airflow | 348, 683, 1,371, 2,040 and 2,725 m³/h, smallest to biggest |
| Noise | 28 dBA (S4), 32 dBA (S6), 39 dBA (S8), 48 dBA (S10) |
| Max power draw | 28W (S4), 64W (S6), 110W (S8), 250W (S10) |
| Motor | EC motor with PWM speed control, rated for 67,000 hours |
| Fan design | Mixed-flow blades with stator elements, built to hold airflow under high static pressure |
| Controller | Manual speed controller in the box. Remembers its setting after a power cut |
| Build | IP44, dual ball bearings, detachable motor housing |
| Power | 100 to 240V, 50/60Hz, UK plug |
| Works with | AC Infinity Controller 69 and the UIS range, such as the UIS Controller 69 Pro |
| Price | From £81.99 (S4) to £349.00 (S12) |
AC Infinity's noise and power figures on our product page stop at the S10, so we haven't quoted them for the S12.
AC Infinity Cloudline S-Series FAQs
Is the AC Infinity Cloudline S-Series any good?
Yes, for most tents and small rooms. It's an EC fan with PWM speed control, it's quiet (28 dBA on the S4, 32 dBA on the S6) and the controller's in the box. If you want temperature and humidity automation from day one, the Cloudline Pro T combos are the better buy.
Cloudline S-Series or Cloudline Pro T-Series?
Same fan, different controller. The S comes with a manual speed controller. The Cloudline Pro T6 combo comes boxed with the UIS Controller 69 Pro for app control, scheduling and climate triggers. At 6 inch the T6 combo is £149.00, which is £39.98 less than an S6 and a 69 Pro bought separately (£188.98).
What size Cloudline S-Series fan do I need?
Match it to your space and to your carbon filter's airflow. Lots of 120cm tents end up on the 6 inch S6 at 683 m³/h. Not sure? Our fan and filter calculator does the sums for you.
How quiet is the Cloudline S-Series?
AC Infinity rate the S4 at 28 dBA, the S6 at 32 dBA, the S8 at 39 dBA and the S10 at 48 dBA. Those are full-speed figures, and it gets quieter as you turn it down. A noise reduction clamp on the duct joints helps with vibration too.
Can I run a Cloudline S-Series fan from an AC Infinity Controller 69?
Yes. AC Infinity list it as compatible with the Controller 69 and the UIS range, so you can add temperature and humidity automation later with something like the UIS Controller 69 Pro.
Does the Cloudline S-Series remember its speed after a power cut?
Yes. The controller has a memory function, so the fan comes back on at the speed you left it.
How do I clean a Cloudline S-Series fan?
Unplug it and take the motor housing off. It's designed to detach, so you can get at the blades and clear the dust before putting it back.
Does the Cloudline S-Series come with a UK plug?
Yes. All the mains products we sell are UK spec with a UK plug, and the fan runs on 100 to 240V, 50/60Hz.
What it does well
Quiet is the headline. AC Infinity rate the 4 inch at 28 dBA and the 6 inch at 32, which matters a lot if the tent lives in a bedroom or a flat with thin walls.
And it doesn't give up once you hang a carbon filter off the end. The mixed-flow blades and stator elements are there to hold airflow up against static pressure. In plain English, a filter and a few metres of duct won't strangle it.
The controller's in the box as well. Plenty of fans make you buy a dimmer separately.
- EC motor that goes easy on the electric. The S6 tops out at 64W
- Remembers its speed after a power cut, so you're not resetting it every time the trip goes
- Motor housing comes off for cleaning
- Rated for 67,000 hours
- Plugs into an AC Infinity Controller 69 Pro when you fancy automating it
Where it falls short
The controller is manual. You pick a speed and it sits there. No temperature triggers and no app. Fine in a tent you look at every day. Less fine in a heatwave when you're at work.
So if you already know you want automation, don't buy the S and add a controller after. The Cloudline Pro T6 combo is the same fan boxed with the UIS Controller 69 Pro for £149.00. An S6 at £97.99 plus a 69 Pro at £90.99 comes to £188.98.
The S10 is the loud one in the family, at 48 dBA and up to 250W. Still EC. Just not whisper territory.
Good fit if you...
- want a quiet fan for a tent or a small room
- run a carbon filter on the end of it
- are happy setting the speed by hand
Look elsewhere if you...
- want climate automation straight out of the box
- are watching every penny on a 6 inch setup (the Phresh Hyper Fan V2 6" is £89.00)
Which version to buy
Pick the fan to match your ducting and your filter. If you need the lot, the kits come with a CarboAir filter sized to the fan and 5m of black combi ducting, and we've checked every one against buying the three bits separately.
| Option | Airflow | Price | Saving |
|---|---|---|---|
| Cloudline S4, 4 inch fan | 348 m³/h | £81.99 | n/a |
| Cloudline S6, 6 inch fan | 683 m³/h | £97.99 | n/a |
| Cloudline S8, 8 inch fan | 1,371 m³/h | £159.00 | n/a |
| Cloudline S10, 10 inch fan | 2,040 m³/h | £259.00 | n/a |
| Cloudline S12, 12 inch fan | 2,725 m³/h | £349.00 | n/a |
| 4 inch kit: S4 + CarboAir 50 + 5m duct | 348 m³/h | £138.95 | £9.49 |
| 6 inch kit: S6 + CarboAir 50 + 5m duct | 683 m³/h | £233.95 | £3.99 |
| 8 inch kit: S8 + CarboAir 60 + 5m duct | 1,371 m³/h | £299.95 | £7.00 |
| 10 inch kit: S10 + CarboAir 50 + 5m duct | 2,040 m³/h | £462.95 | £18.50 |
| 12 inch kit: S12 + CarboAir 50 + 5m duct | 2,725 m³/h | £569.95 | £32.00 |
Savings are against buying the fan, the CarboAir 50 (or CarboAir 60 on the 8 inch) and black combi ducting separately. Prices as at October 2026.
Starting from scratch? Get the kit. Already got a filter you're happy with, just the fan.
How to use it
- Check the filter can keep up. Its m³/h rating should be at least what the fan moves.
- Hang the carbon filter inside the tent, up high, and run a short length of duct from the filter to the fan.
- Take the rest of the duct from the fan out to wherever the air's going.
- Pull every joint tight with the clips from the fan's box and tape any gaps, so the fan isn't sucking air from the wrong place.
- Plug the controller in and pick a speed. Start low and work up until the tent walls pull in slightly.
- Fancy automation later? Plug it into an AC Infinity Controller 69 instead.
Looking after it
Not much to it, which is rather the point.
- Clean it now and then. Unplug it, detach the motor housing and clear the dust off. That's what the detachable housing is there for.
- Keep the filter breathing. A clogged pre-filter makes the fan work harder for less. On a CarboAir 50, a replacement sleeve is from £4.95.
- Check the joints. A loose clip leaks air and can rattle. A noise reduction clamp seals the joint and soaks up some of the vibration.
- Mind the water. IP44 copes with splashes. It's not meant for a soaking.
How it stacks up
All compared at 6 inch, the size most tents end up on.
| Fan | Airflow | Max power | Controller in the box | Price |
|---|---|---|---|---|
| AC Infinity Cloudline S6 | 683 m³/h | 64W | Manual speed controller | £97.99 |
| AC Infinity Cloudline Pro T6 combo | 402 CFM (683 m³/h) | 70W | UIS Controller 69 Pro | £149.00 |
| Rhino Ultra EC Fan | 594 m³/h | 40W | Varispeed controller | £119.94 |
| Phresh Hyper Fan V2 | 560 m³/h | 42W | Manual speed controller | £89.00 |
Figures from each product page. Makers measure noise in their own way, so we've left dBA out of this one. Prices as at October 2026.
The S6 moves the most air per pound of the four. The T6 combo costs more, but most of that is the smart controller. For how to size the fan and filter together, have a read of our grow room extraction guide, and the best carbon filters guide covers the other end of the duct.
Got a question about it? Give us a ring on 020 8686 9643 or email info@thehydrobros.com.
Or pop into the shop and have a look at one: Unit 12, Progress Business Park, Progress Way, Croydon CR0 4XD.
More grow guides
- Grow room extraction: choosing a fan and filter
- Best carbon filters for grow tents
- Best grow tents by size
- Best LED grow lights for a 120cm tent
- AC Infinity Spectron 7: a closer look
- How to cool down a grow tent
The Hydro Bros Team. We sell this kit and talk growers through it every day in our Croydon shop.
