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Description
The K Fan EC is the EC-motor version of the German-built K Series circular duct fan — the same industrial ventilation platform behind the Systemair RVK, but with the motor control and protection electronics built into the fan itself.
Because an EC (electronically commutated) motor varies its speed by changing the motor's actual drive frequency rather than by throttling the voltage, it runs smoothly right down to low speeds with no hum, no buzz and no transformer whine — and it draws only the power it actually needs. Global Air Supplies quote a saving of over 50% on running cost against the equivalent K Fan AC.
- EC motor with integrated control and protection electronics
- 0–10V speed control — runs quietly at low speed, no humming
- Over 50% lower running cost than the equivalent AC fan
- Built-in thermal overload protection
- Maintenance-free galvanised steel casing
- Made in Germany
- 2 year manufacturer warranty
Please read before you order — this fan does not come ready to plug in
To power it, you need a 13A stripped-end lead. The K Fan EC has no plug and no kettle-lead socket. It terminates in a sealed IP55 terminal box, so the mains supply is wired directly into the fan. The part you need is the 13A Fitted Plug with Stripped End (3m) — moulded UK plug at one end, bare conductors at the other, ready to land straight into the terminal block. Five minutes for anyone comfortable wiring a plug; if that is not you, have an electrician do it.
To run it from a controller, you also need a Pack 8 cable. The K Fan EC talks to G.A.S. digital controllers over their own connector, so add a GAS Digital EC Cable (Pack 8) — 5m Active Male to Male. That is the one for a single fan into a single controller. Running two fans off one controller? Add a Pack 9 Active Y-Splitter as well.
Which controller? For straightforward speed control, the GAS AC-EC Fan Speed Controller handles both EC and AC fans and is the natural pairing. If you want temperature and humidity control, or you have more kit to run than just a fan, step up to the GAS Enviro Controller V4 (26A) — it manages your environment rather than just your fan speed. Both are in the fan speed controller range. Running a TrolMaster? See the section below.
Before you buy — two more things worth knowing
1. An EC fan needs an EC controller. This is the single most common mistake we see. You cannot run an EC fan from a standard AC / triac voltage controller such as the SMS Twin — it will not work and you risk damaging the electronics. The K Fan EC takes a 0–10V signal, which is why the controllers listed above are the ones to pair it with.
2. The airflow figures are free-air maximums. Every quoted m³/h figure on every fan on the market is measured with nothing attached. Put a carbon filter on the intake and a few metres of ducting on the outlet and you will realistically see 60–75% of that number. Size up accordingly rather than buying exactly to your calculated requirement.
Running it on a TrolMaster Tent-X or Hydro-X
You need two parts — the EFC-1 and a Pack 8 cable
TrolMaster controllers do not take the G.A.S. connector directly, so there is one adaptor in the middle. Add both of these to your order:
- TrolMaster EC Fan Controller (EFC-1) — the adaptor that plugs into your Tent-X (TCS-1) or Hydro-X base station
- GAS Digital EC Cable (Pack 8) — the lead between the fan and the EFC-1
How they join up: the Pack 8 plugs into the fan at one end. The other end you cut off, strip the conductors back, and land them into the terminal block on the EFC-1. The EFC-1 then plugs into your Tent-X or Hydro-X on its RJ12 lead.
Do not go by the wire colours. The colour coding on these cables has changed more than once, so older guides and diagrams no longer match what is in the box — which is why we do not publish a colour code. Work it out by trial and error instead. This is the low-voltage 0–10V control pair, not mains, so nothing is at risk if you get it the wrong way round: the fan simply will not respond to the controller. Try each combination, change the setpoint on the controller, and watch for the fan speed responding. Stop when it does. Only ever cut and rewire the Pack 8 control cable — never the 13A mains lead. If you get stuck, give us a ring and we will talk you through it.
Sizes and airflow
| Model | Duct size | Max airflow (m³/h) | Typical tent |
|---|---|---|---|
| K 100 EC | 4" / 100mm | 321 | Up to 80 x 80cm |
| K 125 EC | 5" / 125mm | 482 | 80 x 80 to 100 x 100cm |
| K 150 EC | 6" / 150mm | 598 | 100 x 100 to 120 x 120cm |
| K 200 EC | 8" / 200mm | 774 | 120 x 120 to 150 x 150cm |
| K 250 EC | 10" / 250mm | 1033 | Small grow room |
| K 315M EC | 12" / 315mm | 1415 | Grow room |
| K 315L EC | 12" / 315mm (long body) | 1734 | Large grow room |
Specification
| Detail | Value |
|---|---|
| Motor type | EC, integrated control electronics |
| Supply | 230V, 50/60Hz, single phase |
| Speed control | 0–10V via G.A.S. digital controller (Pack 8 cable required) |
| Mains connection | IP55 terminal box (hard wired, no plug or lead supplied) |
| Motor protection | IP44 (terminal box IP55, cable gland IP68) |
| Insulation class | B |
| Max air temperature | 40°C |
| Casing | Galvanised sheet steel |
| Warranty | 2 years |
| Origin | Made in Germany |
As a worked example, the K 315M EC draws 166W at 2117rpm for 1415 m³/h, weighs 6kg, and measures 314mm bore x 408mm casing diameter. Figures published by Systemair.
What else you will need
- 13A Fitted Plug with Stripped End (3m) — required, this is how the fan gets its mains supply
- GAS Digital EC Cable (Pack 8) 5m Active Male to Male — required if you are running the fan from a controller
- GAS AC-EC Fan Speed Controller — speed control for EC and AC fans
- GAS Enviro Controller V4 (26A) — full temperature and humidity control when you have more than a fan to manage
- TrolMaster EC Fan Controller (EFC-1) — only if you are running the fan from a TrolMaster Tent-X or Hydro-X
- Rhino Pro Carbon Filter — match the filter's m³/h rating to the fan, not the other way round
- Phonic Trap Ultra Silent Acoustic Ducting or standard acoustic ducting — the fan is quiet, so duct noise becomes the loudest part of the system
- Quick Connection Kit and jubilee duct clips for a secure, leak-free join
Alternatives worth comparing
We would rather you bought the right fan than the most expensive one. Here is how the K Fan EC sits against the rest of our range.
| Fan | Type | Why you might pick it instead |
|---|---|---|
| Rhino Ultra Silenced EC Fan | EC, acoustically insulated | Similar money, similar airflow, but wrapped in acoustic insulation. If noise is your priority this is usually the better buy. |
| Air EC Fan | EC, entry level | The budget route into EC. Less refined and a shorter warranty, but a big step up from any AC fan on running cost. |
| Systemair RVK | AC | Same German factory, same reliability, a fraction of the price. You lose the quiet low-speed running and the efficiency. |
| Can-Fan Isomax | AC, silenced | The classic quiet AC option, with a stator-rotor design that keeps noise down without EC electronics. |
| Revolution Super Silent Vector EC | EC, high power | When 1734 m³/h is not enough. 315mm and 355mm, up to 5929 m³/h. |
| Air AC Fan | AC, entry level | The cheapest way to move air in a single tent, if budget is the deciding factor. |
Browse the full EC fan range or the AC duct fan range.
Frequently asked questions
What is the difference between an EC fan and an AC fan?
An AC fan runs at a fixed speed set by the mains frequency, and you slow it down by reducing the voltage — which is what causes the hum and buzz you get from a cheap controller at low speed. An EC fan has a DC motor with a built-in inverter that generates its own drive frequency, so it can be told to run at any speed and does so smoothly and quietly. EC motors are also substantially more efficient, particularly at part load, which is where most extraction fans spend their lives.
Can I use my existing SMS or triac fan controller with the K Fan EC?
No. Voltage-regulating AC controllers such as the SMS Twin will not control an EC fan and may damage it. You need a 0–10V controller. The GAS AC-EC Fan Speed Controller handles both AC and EC fans, so it will cover you if you are running a mixed setup, and the GAS Enviro Controller V4 adds temperature and humidity control on top. Either way you will also need a Pack 8 EC cable to connect the fan to the controller.
Can I run the K Fan EC from a TrolMaster Tent-X?
Yes, with two extra parts. You need the TrolMaster EC Fan Controller (EFC-1), which is the adaptor that plugs into your Tent-X (TCS-1), and a GAS Digital EC Cable (Pack 8) to bridge the fan to it. The Pack 8 plugs into the fan at one end; you cut the other end off and wire the bare conductors into the EFC-1's terminal block. Ignore the wire colours — they have changed between batches, so it is a matter of trying each combination until the fan responds when you move the setpoint. It is a low-voltage control signal, so a wrong combination does no damage. The same applies to a Hydro-X base station.
Does the K Fan EC come with a plug or a lead?
No — and it does not take a kettle lead either. The K Series uses a sealed IP55 terminal box, so the mains supply is wired directly into the fan. Add a 13A Fitted Plug with Stripped End (3m) to your order: moulded UK plug at one end, stripped conductors at the other, which land straight into the terminal block. It is the same lead our RVK customers use. If you would rather have something you can simply plug in and go, the Rhino Ultra Silenced EC is the one to look at.
How do I wire it up?
Unscrew the lid of the terminal box on the side of the fan casing, feed the stripped end of the 13A lead through the cable gland, and land live, neutral and earth on the marked terminals. Tighten the gland so the seal is made and refit the lid. The control side is simpler — the Pack 8 cable plugs straight into the fan at one end and your controller at the other, no wiring involved. If you are not confident with the mains side, have an electrician do it; it is a ten minute job for them.
Which EC cable do I need — Pack 8 or something else?
For one fan into one controller, the Pack 8 (5m Active Male to Male) is the one. If you want to run two fans from a single controller channel, add a Pack 9 Active Y-Splitter. Need more reach? The Pack 11 Active Female to Female Extension adds length to an existing run. If you are unsure, tell us your fan, your controller and the distance between them and we will tell you exactly what to order.
What size K Fan EC do I need for my tent?
As a rule of thumb, work out the volume of your space in cubic metres and aim to exchange the air once every one to three minutes, then add roughly 30–40% headroom for the resistance of a carbon filter and ducting. A 120 x 120 x 200cm tent is 2.88m³, so you want somewhere around 350–500 m³/h of real-world airflow — which is the 6" or 8" in this range once the filter is accounted for.
Which way round does it go?
Airflow direction is marked on the casing. For odour control you want the carbon filter on the intake side, inside the tent, pulling air through the filter and then out through the fan — not blowing into it.
Is it quiet?
For an uninsulated inline fan, yes — particularly at reduced speed, where an EC motor has a real advantage over AC. But it is a bare metal fan, not a boxed acoustic unit. If silence matters more than anything else, either pair it with Phonic Trap acoustic ducting or look at the Rhino Ultra Silenced EC, which is insulated as standard.
What is the warranty?
Two years from the manufacturer. The motor is maintenance-free and has thermal overload protection built in.
K Series fan specifications published by Systemair. K Fan EC supplied in the UK by Global Air Supplies.
Shipping
1. UK SHIPPING COSTS
Here’s the deal:
Orders under £99: £8.49 shipping
Orders £99 or more: FREE shipping 🎉
BUT… bulky or awkward items still carry a surcharge:
£5 per 50L soil bag
£15 for large tents, trays, 6ft poles, etc.
£2.50 per extra 5KG of Coco bricks (over 15KG)
Anything that needs to go on a pallet; from £60 pallet
If you're in the Highlands, Islands, NI, or similar, there's a flat £27 charge + any surcharges. These all get added automatically at checkout.
1.1 Missed or Failed Deliveries
If your parcel comes back to us because you weren't in, didn't collect it, gave us the wrong contact/address details, or didn't respond to the courier, we'll offer to resend or refund:
Resend – the reship fee is whatever you paid for shipping the first time round. If your original order had free shipping, we'll work out the reship cost based on what it actually costs to send it again.
Pallet items – reship starts from £60, but can be more for remote areas (Highlands, Islands, NI, etc.) – same surcharges that applied the first time.
Refund instead – minus courier costs and a 15% admin/restocking fee. See our Refund Policy for how refunds work.
Please double-check your delivery details and track your parcel to avoid this altogether.
International missed/failed deliveries follow the international section below – courier and customs costs plus the 15% fee apply, there's no flat reship rate.
2. UK SHIPPING TIMES
We usually dispatch within 1–2 working days, and send on a next-day delivery after that (mainland UK). However, some parts of the UK like Scottish Highlands, may take 2 days to ship.
Some delays are out of our hands (stock levels, courier hiccups, bank holidays, peak sales), so please allow up to 5 working days before chasing.
Need it urgently or on a Saturday? Call 020 8686 9643 first and we'll help.
2.1 Previously Used Courier Preferences
If you've ever told a courier “leave it in the shed/porch/bushes” – that preference may stick. They might do it again even if you didn't ask this time.
We're not responsible for items lost, damaged or stolen due to these delivery instructions. If in doubt, let us know in advance and we'll try to override it.
3. INTERNATIONAL SHIPPING
3.1 Do You Ship Abroad?
Yes, we ship worldwide 🌍
UK VAT is removed where applicable. Local VAT, customs duties and import charges may then apply when your parcel enters its destination country.
Ordering from Germany? Gute Nachrichten! 🇩🇪
We are now German VAT registered and send German orders DDP. This means the relevant VAT and customs charges are handled by us, with nothing extra for you to pay when your parcel arrives. Almost like we're part of Europe again!
For every other country outside the UK, orders ship DAP – that's standard for goods sent from the UK. Your order price doesn't include the destination country's VAT or duty, so local VAT, customs duties, clearance charges and any courier handling fee are your responsibility when your parcel arrives.
We ship in good faith, but it is your responsibility to check whether the products you order are permitted in your country. With more than 7,000 products, we cannot monitor every local restriction.
3.1b UK Specification: Plugs & Voltage
All our electrical products are UK spec – UK plug, UK 230-240V voltage.
If you're ordering from outside the UK, it's on you to sort out a plug adapter or rewire, and to check your local voltage is compatible. We don't rewire, re-plug, or convert voltage before dispatch, and we're not liable for damage caused by using UK-spec electrical items on an incompatible supply. If you're not sure your setup can take a UK-spec item, check before you order.
3.2 Shipping Costs
Our system is not perfect yet. Standard EU shipping normally starts from around €35, but if the actual cost is higher, we will contact you before dispatch.
You can pay the difference or cancel the order for a full refund.
Want a quote before ordering? Email info@thehydrobros.com, or select bank deposit at checkout so we can review the order before payment.
3.3 How Long Will It Take?
Europe: Usually 2 to 4 working days, although customs can add delays
USA: Surprisingly quick, sometimes around 2 working days
Rest of the world: Usually up to 7 working days or longer, depending on customs
Tracking will be provided as soon as your order leaves us.
3.4 Customs and VAT
International orders may be subject to local VAT, customs duties, clearance charges and additional paperwork.
Please provide a valid email address and phone number so the courier or customs authority can contact you if needed.
Germany is the exception. German orders are sent DDP, so we handle the relevant import charges and you should not be asked to pay anything extra on delivery.
3.5 Temporary EU Customs Duty
From 1 July 2026, the EU introduced a temporary customs duty on qualifying low-value parcels entering the EU from outside the EU.
For consignments with an intrinsic goods value of €150 or less, the duty is generally charged at €3 per customs item or tariff classification, rather than simply €3 per parcel.
For example:
- Several identical products under one tariff classification may attract one €3 charge
- Products under two different tariff classifications may attract two €3 charges
This duty is collected by the courier or destination customs authority when your parcel arrives – not by us at checkout – so it'll show up as part of what's due on delivery, alongside any local VAT.
This measure is temporary because it acts as a bridge while the EU prepares its permanent customs system. It is currently intended to apply until 1 July 2028. After that, low-value goods are expected to move onto the permanent system, where normal customs tariff rates will apply according to the type and origin of each product.
This temporary customs duty is separate from VAT and is also separate from the proposed EU parcel handling fee, which is a different measure.
3.6 What If You Don't Pay Customs Fees?
No payment means no parcel.
If you ignore a customs payment request, the parcel may be delayed, returned or destroyed.
If it is returned to us, your refund will be reduced by:
- Original shipping costs
- Return courier charges
- Any unpaid customs or carrier charges billed back to us
- A 15% administration and restocking fee
If the parcel is destroyed, abandoned or lost because the required charges were not paid, no refund will be issued.
This does not apply to German DDP orders where the relevant charges are being handled by us.
3.6b What If Your Country Won't Let It In?
We'll ship almost anything to almost anywhere – if it fits in a box, we can put a label on it and hand it to the courier. But getting it through customs at the other end is on you.
It's your job to know:
- Whether the product you're ordering is legal to import into your country
- Whether it needs a licence, certificate, or extra paperwork to clear customs
- Whether restrictions apply to that item specifically (voltage, plant nutrients, electricals, batteries, etc. – rules vary wildly by country)
With over 7,000 products shipping worldwide, we can't check every country's import rules for every item – so we don't, and we won't be held responsible for a parcel that gets stopped because it wasn't allowed in, or because customs wanted paperwork you couldn't provide.
If your parcel is delayed, returned, or destroyed because of import restrictions or missing paperwork on your end, the same terms as 3.6 above apply:
- Original shipping costs (non-refundable)
- Return courier charges
- Any customs or carrier fees billed back to us
- A 15% admin/restocking fee
If it's abandoned or destroyed rather than returned, no refund will be issued.
Not sure if something can legally land in your country? Check with your own customs authority before you order – not after it gets stuck.
3.7 Faulty Products
For overseas orders, you're responsible for the shipping costs of any return, repair, or replacement – including if the item is faulty – unless we've confirmed otherwise with you in writing.
3.8 International Summary
For most international destinations, customs rules, local taxes, duties and paperwork are your responsibility.
For Germany, we are VAT registered and ship DDP, so there should be nothing extra to pay when your parcel arrives.
For qualifying EU consignments worth €150 or less, a temporary customs duty may apply on delivery. This is normally calculated at €3 per customs item or tariff classification, and is collected by the courier or customs authority – not by us at checkout.
Check before buying if you are unsure. It saves everyone a headache.
Returns
Thank you for shopping with The Hydro Bros. We hope you're happy with your purchase — but if you've changed your mind, ordered the wrong item, or need to return something, here's how it works.
How long do I have to return something?
You have 14 working days from the day your order is delivered to request a return. All returns must meet the following conditions to be accepted.
What are the return conditions?
To be eligible for a return:
The item must be unopened, unused, and in original condition
All packaging must be intact, including outer boxes and security seals
The product must be returned in "box-fresh" condition — clean, untorn, and free from tape, labels, or writing
Faulty items must be returned in full for inspection
Returns are only accepted from end consumers, not businesses purchasing for resale
Returns must be authorised by us before sending anything back — contact info@thehydrobros.com
Who pays for return shipping?
If the item is not faulty, you are responsible for the return shipping costs.
We recommend using a tracked and insured service — the item remains your responsibility until it arrives back with us.
What if I reject the delivery or miss it?
If you refuse delivery or fail to collect your parcel and it gets returned to us, we'll offer to resend or refund:
Resend — the reship fee is whatever you paid for shipping originally. If your original order had free shipping, we'll calculate the reship cost based on what it actually costs to send it again. Pallet items start from £60, and can be more for remote areas (Highlands, Islands, NI, etc.).
Refund instead — minus the original delivery cost, reship/return costs, and a 15% restocking and handling fee.
Full detail on missed and failed deliveries is on our Shipping Policy.
Will I get a full refund?
If your return is accepted, we'll issue a refund minus:
The original delivery cost (even if not listed separately at checkout)
A 15% restocking and handling fee
These fees help cover the cost of inspection, repackaging, and processing — returns aren't free to manage, and this keeps pricing fair for all customers.
Why do you charge a restocking fee?
Hydroponic gear often requires careful inspection, cleaning, and handling to be resold safely. The 15% restocking fee helps cover these operational costs and allows us to continue offering competitive prices across the board.
What if my item is faulty?
If you believe an item is faulty, contact us first with photos/videos to verify the issue. If confirmed, we'll guide you through the return process and offer a like-for-like replacement.
If the item is returned and found to be fully functional, the return will be treated as a standard one — and all standard fees will apply (delivery + 15%).
For orders shipped outside the UK, you're responsible for the shipping costs of any return, repair, or replacement — including if the item is faulty — unless we've confirmed otherwise with you in writing. See our Shipping Policy for international shipping details.
What happens if I return something in poor condition?
If the item is:
Used,
Damaged,
Missing parts, or
Returned with torn, marked, or taped-up packaging,
We reserve the right to refuse the refund entirely.
You'll then have two options:
Arrange return shipping at your own cost
Leave the item with us — if unclaimed after 28 days, we will responsibly dispose of it
Cancellations
Can I cancel my order?
Yes. Under UK distance selling rules, you have 14 days after receiving your order to cancel it entirely. The same return conditions as above apply — unopened, unused, original packaging, box-fresh.
What if I cancel after it's already shipped?
You'll get a refund once we receive the item back, minus the cost of shipping and a 15% admin fee.
What if the returned item isn't in as-supplied condition?
If it's been opened, used, or marked, we reserve the right to treat it as a partial loss and refund a clearance value rather than the full amount paid.
Damages & Receiving Your Order
What should I do when my parcel arrives?
Inspect it for damage before you sign for it. If there's any sign of damage, tell the courier in writing at the point of signing — and keep all packaging in case you need to make a claim.
What if I sign for it without mentioning damage?
We can't accept a damage claim for a parcel you've signed for without noting damage at the time. Once signed for, any damage found afterwards is treated as having happened after delivery.
What if something's missing from my order, or the wrong item's inside, or it's damaged in transit?
Open your parcel and check the contents as soon as it arrives. You need to report transit damage, missing items, or wrong items within 24 hours of delivery.
We get contacted weeks — sometimes months — after delivery by people who never opened the box, saying an item's missing or damaged. We can't do anything with that. No packaging, no timely report, no proof it didn't happen after the fact — there's nothing to investigate and nothing we can action. Check your order when it lands, not when you finally get round to using it.
What if an item develops a fault later on?
That's a different situation to transit damage — see the Faulty Items section above. There's no 24-hour cutoff for genuine faults; contact us with photos/videos when the issue shows up and we'll take it from there.
What if my order doesn't arrive when expected?
Let us know within 2 days of the expected delivery date — that gives us the best chance of sorting it.
What if my parcel goes missing entirely?
You must tell us in writing within 7 days of the expected delivery date. Couriers have a claim window, so if we're not told in time, we can't make a claim and can't refund the loss.
Are damage claims accepted for items caused by misuse or abuse?
No — we don't accept return or damage claims resulting from physical damage or abuse after delivery.
Lost Parcels
What happens if my parcel goes missing?
We'll open an investigation and claim with the courier. You'll need to participate — this may include completing and signing a legal declaration form to support the claim.
How long does this take?
Once the claim is approved, a refund can take up to 10 working days to process.
Refund Timing
How will I know if my refund is approved?
We'll notify you once we've received and inspected your return, and confirm whether it's been approved.
How do I get paid back?
Approved refunds go back to your original payment method automatically, minus any deductions covered elsewhere on this page (shipping costs on non-fault returns/cancellations, restocking fees, condition deductions).
How long does it take to arrive?
Please allow 10 working days from refund confirmation for the money to actually land back with you — your bank or card provider can add extra processing time on their end.
Not sure what size fan or filter you need?
Enter your grow room dimensions and we'll match you to the right fan and carbon filter — instantly.
Over 15,000 Customers
Croydon Shop
Price Match
Pay Later
Description
The K Fan EC is the EC-motor version of the German-built K Series circular duct fan — the same industrial ventilation platform behind the Systemair RVK, but with the motor control and protection electronics built into the fan itself.
Because an EC (electronically commutated) motor varies its speed by changing the motor's actual drive frequency rather than by throttling the voltage, it runs smoothly right down to low speeds with no hum, no buzz and no transformer whine — and it draws only the power it actually needs. Global Air Supplies quote a saving of over 50% on running cost against the equivalent K Fan AC.
- EC motor with integrated control and protection electronics
- 0–10V speed control — runs quietly at low speed, no humming
- Over 50% lower running cost than the equivalent AC fan
- Built-in thermal overload protection
- Maintenance-free galvanised steel casing
- Made in Germany
- 2 year manufacturer warranty
Please read before you order — this fan does not come ready to plug in
To power it, you need a 13A stripped-end lead. The K Fan EC has no plug and no kettle-lead socket. It terminates in a sealed IP55 terminal box, so the mains supply is wired directly into the fan. The part you need is the 13A Fitted Plug with Stripped End (3m) — moulded UK plug at one end, bare conductors at the other, ready to land straight into the terminal block. Five minutes for anyone comfortable wiring a plug; if that is not you, have an electrician do it.
To run it from a controller, you also need a Pack 8 cable. The K Fan EC talks to G.A.S. digital controllers over their own connector, so add a GAS Digital EC Cable (Pack 8) — 5m Active Male to Male. That is the one for a single fan into a single controller. Running two fans off one controller? Add a Pack 9 Active Y-Splitter as well.
Which controller? For straightforward speed control, the GAS AC-EC Fan Speed Controller handles both EC and AC fans and is the natural pairing. If you want temperature and humidity control, or you have more kit to run than just a fan, step up to the GAS Enviro Controller V4 (26A) — it manages your environment rather than just your fan speed. Both are in the fan speed controller range. Running a TrolMaster? See the section below.
Before you buy — two more things worth knowing
1. An EC fan needs an EC controller. This is the single most common mistake we see. You cannot run an EC fan from a standard AC / triac voltage controller such as the SMS Twin — it will not work and you risk damaging the electronics. The K Fan EC takes a 0–10V signal, which is why the controllers listed above are the ones to pair it with.
2. The airflow figures are free-air maximums. Every quoted m³/h figure on every fan on the market is measured with nothing attached. Put a carbon filter on the intake and a few metres of ducting on the outlet and you will realistically see 60–75% of that number. Size up accordingly rather than buying exactly to your calculated requirement.
Running it on a TrolMaster Tent-X or Hydro-X
You need two parts — the EFC-1 and a Pack 8 cable
TrolMaster controllers do not take the G.A.S. connector directly, so there is one adaptor in the middle. Add both of these to your order:
- TrolMaster EC Fan Controller (EFC-1) — the adaptor that plugs into your Tent-X (TCS-1) or Hydro-X base station
- GAS Digital EC Cable (Pack 8) — the lead between the fan and the EFC-1
How they join up: the Pack 8 plugs into the fan at one end. The other end you cut off, strip the conductors back, and land them into the terminal block on the EFC-1. The EFC-1 then plugs into your Tent-X or Hydro-X on its RJ12 lead.
Do not go by the wire colours. The colour coding on these cables has changed more than once, so older guides and diagrams no longer match what is in the box — which is why we do not publish a colour code. Work it out by trial and error instead. This is the low-voltage 0–10V control pair, not mains, so nothing is at risk if you get it the wrong way round: the fan simply will not respond to the controller. Try each combination, change the setpoint on the controller, and watch for the fan speed responding. Stop when it does. Only ever cut and rewire the Pack 8 control cable — never the 13A mains lead. If you get stuck, give us a ring and we will talk you through it.
Sizes and airflow
| Model | Duct size | Max airflow (m³/h) | Typical tent |
|---|---|---|---|
| K 100 EC | 4" / 100mm | 321 | Up to 80 x 80cm |
| K 125 EC | 5" / 125mm | 482 | 80 x 80 to 100 x 100cm |
| K 150 EC | 6" / 150mm | 598 | 100 x 100 to 120 x 120cm |
| K 200 EC | 8" / 200mm | 774 | 120 x 120 to 150 x 150cm |
| K 250 EC | 10" / 250mm | 1033 | Small grow room |
| K 315M EC | 12" / 315mm | 1415 | Grow room |
| K 315L EC | 12" / 315mm (long body) | 1734 | Large grow room |
Specification
| Detail | Value |
|---|---|
| Motor type | EC, integrated control electronics |
| Supply | 230V, 50/60Hz, single phase |
| Speed control | 0–10V via G.A.S. digital controller (Pack 8 cable required) |
| Mains connection | IP55 terminal box (hard wired, no plug or lead supplied) |
| Motor protection | IP44 (terminal box IP55, cable gland IP68) |
| Insulation class | B |
| Max air temperature | 40°C |
| Casing | Galvanised sheet steel |
| Warranty | 2 years |
| Origin | Made in Germany |
As a worked example, the K 315M EC draws 166W at 2117rpm for 1415 m³/h, weighs 6kg, and measures 314mm bore x 408mm casing diameter. Figures published by Systemair.
What else you will need
- 13A Fitted Plug with Stripped End (3m) — required, this is how the fan gets its mains supply
- GAS Digital EC Cable (Pack 8) 5m Active Male to Male — required if you are running the fan from a controller
- GAS AC-EC Fan Speed Controller — speed control for EC and AC fans
- GAS Enviro Controller V4 (26A) — full temperature and humidity control when you have more than a fan to manage
- TrolMaster EC Fan Controller (EFC-1) — only if you are running the fan from a TrolMaster Tent-X or Hydro-X
- Rhino Pro Carbon Filter — match the filter's m³/h rating to the fan, not the other way round
- Phonic Trap Ultra Silent Acoustic Ducting or standard acoustic ducting — the fan is quiet, so duct noise becomes the loudest part of the system
- Quick Connection Kit and jubilee duct clips for a secure, leak-free join
Alternatives worth comparing
We would rather you bought the right fan than the most expensive one. Here is how the K Fan EC sits against the rest of our range.
| Fan | Type | Why you might pick it instead |
|---|---|---|
| Rhino Ultra Silenced EC Fan | EC, acoustically insulated | Similar money, similar airflow, but wrapped in acoustic insulation. If noise is your priority this is usually the better buy. |
| Air EC Fan | EC, entry level | The budget route into EC. Less refined and a shorter warranty, but a big step up from any AC fan on running cost. |
| Systemair RVK | AC | Same German factory, same reliability, a fraction of the price. You lose the quiet low-speed running and the efficiency. |
| Can-Fan Isomax | AC, silenced | The classic quiet AC option, with a stator-rotor design that keeps noise down without EC electronics. |
| Revolution Super Silent Vector EC | EC, high power | When 1734 m³/h is not enough. 315mm and 355mm, up to 5929 m³/h. |
| Air AC Fan | AC, entry level | The cheapest way to move air in a single tent, if budget is the deciding factor. |
Browse the full EC fan range or the AC duct fan range.
Frequently asked questions
What is the difference between an EC fan and an AC fan?
An AC fan runs at a fixed speed set by the mains frequency, and you slow it down by reducing the voltage — which is what causes the hum and buzz you get from a cheap controller at low speed. An EC fan has a DC motor with a built-in inverter that generates its own drive frequency, so it can be told to run at any speed and does so smoothly and quietly. EC motors are also substantially more efficient, particularly at part load, which is where most extraction fans spend their lives.
Can I use my existing SMS or triac fan controller with the K Fan EC?
No. Voltage-regulating AC controllers such as the SMS Twin will not control an EC fan and may damage it. You need a 0–10V controller. The GAS AC-EC Fan Speed Controller handles both AC and EC fans, so it will cover you if you are running a mixed setup, and the GAS Enviro Controller V4 adds temperature and humidity control on top. Either way you will also need a Pack 8 EC cable to connect the fan to the controller.
Can I run the K Fan EC from a TrolMaster Tent-X?
Yes, with two extra parts. You need the TrolMaster EC Fan Controller (EFC-1), which is the adaptor that plugs into your Tent-X (TCS-1), and a GAS Digital EC Cable (Pack 8) to bridge the fan to it. The Pack 8 plugs into the fan at one end; you cut the other end off and wire the bare conductors into the EFC-1's terminal block. Ignore the wire colours — they have changed between batches, so it is a matter of trying each combination until the fan responds when you move the setpoint. It is a low-voltage control signal, so a wrong combination does no damage. The same applies to a Hydro-X base station.
Does the K Fan EC come with a plug or a lead?
No — and it does not take a kettle lead either. The K Series uses a sealed IP55 terminal box, so the mains supply is wired directly into the fan. Add a 13A Fitted Plug with Stripped End (3m) to your order: moulded UK plug at one end, stripped conductors at the other, which land straight into the terminal block. It is the same lead our RVK customers use. If you would rather have something you can simply plug in and go, the Rhino Ultra Silenced EC is the one to look at.
How do I wire it up?
Unscrew the lid of the terminal box on the side of the fan casing, feed the stripped end of the 13A lead through the cable gland, and land live, neutral and earth on the marked terminals. Tighten the gland so the seal is made and refit the lid. The control side is simpler — the Pack 8 cable plugs straight into the fan at one end and your controller at the other, no wiring involved. If you are not confident with the mains side, have an electrician do it; it is a ten minute job for them.
Which EC cable do I need — Pack 8 or something else?
For one fan into one controller, the Pack 8 (5m Active Male to Male) is the one. If you want to run two fans from a single controller channel, add a Pack 9 Active Y-Splitter. Need more reach? The Pack 11 Active Female to Female Extension adds length to an existing run. If you are unsure, tell us your fan, your controller and the distance between them and we will tell you exactly what to order.
What size K Fan EC do I need for my tent?
As a rule of thumb, work out the volume of your space in cubic metres and aim to exchange the air once every one to three minutes, then add roughly 30–40% headroom for the resistance of a carbon filter and ducting. A 120 x 120 x 200cm tent is 2.88m³, so you want somewhere around 350–500 m³/h of real-world airflow — which is the 6" or 8" in this range once the filter is accounted for.
Which way round does it go?
Airflow direction is marked on the casing. For odour control you want the carbon filter on the intake side, inside the tent, pulling air through the filter and then out through the fan — not blowing into it.
Is it quiet?
For an uninsulated inline fan, yes — particularly at reduced speed, where an EC motor has a real advantage over AC. But it is a bare metal fan, not a boxed acoustic unit. If silence matters more than anything else, either pair it with Phonic Trap acoustic ducting or look at the Rhino Ultra Silenced EC, which is insulated as standard.
What is the warranty?
Two years from the manufacturer. The motor is maintenance-free and has thermal overload protection built in.
K Series fan specifications published by Systemair. K Fan EC supplied in the UK by Global Air Supplies.
Shipping
1. UK SHIPPING COSTS
Here’s the deal:
Orders under £99: £8.49 shipping
Orders £99 or more: FREE shipping 🎉
BUT… bulky or awkward items still carry a surcharge:
£5 per 50L soil bag
£15 for large tents, trays, 6ft poles, etc.
£2.50 per extra 5KG of Coco bricks (over 15KG)
Anything that needs to go on a pallet; from £60 pallet
If you're in the Highlands, Islands, NI, or similar, there's a flat £27 charge + any surcharges. These all get added automatically at checkout.
1.1 Missed or Failed Deliveries
If your parcel comes back to us because you weren't in, didn't collect it, gave us the wrong contact/address details, or didn't respond to the courier, we'll offer to resend or refund:
Resend – the reship fee is whatever you paid for shipping the first time round. If your original order had free shipping, we'll work out the reship cost based on what it actually costs to send it again.
Pallet items – reship starts from £60, but can be more for remote areas (Highlands, Islands, NI, etc.) – same surcharges that applied the first time.
Refund instead – minus courier costs and a 15% admin/restocking fee. See our Refund Policy for how refunds work.
Please double-check your delivery details and track your parcel to avoid this altogether.
International missed/failed deliveries follow the international section below – courier and customs costs plus the 15% fee apply, there's no flat reship rate.
2. UK SHIPPING TIMES
We usually dispatch within 1–2 working days, and send on a next-day delivery after that (mainland UK). However, some parts of the UK like Scottish Highlands, may take 2 days to ship.
Some delays are out of our hands (stock levels, courier hiccups, bank holidays, peak sales), so please allow up to 5 working days before chasing.
Need it urgently or on a Saturday? Call 020 8686 9643 first and we'll help.
2.1 Previously Used Courier Preferences
If you've ever told a courier “leave it in the shed/porch/bushes” – that preference may stick. They might do it again even if you didn't ask this time.
We're not responsible for items lost, damaged or stolen due to these delivery instructions. If in doubt, let us know in advance and we'll try to override it.
3. INTERNATIONAL SHIPPING
3.1 Do You Ship Abroad?
Yes, we ship worldwide 🌍
UK VAT is removed where applicable. Local VAT, customs duties and import charges may then apply when your parcel enters its destination country.
Ordering from Germany? Gute Nachrichten! 🇩🇪
We are now German VAT registered and send German orders DDP. This means the relevant VAT and customs charges are handled by us, with nothing extra for you to pay when your parcel arrives. Almost like we're part of Europe again!
For every other country outside the UK, orders ship DAP – that's standard for goods sent from the UK. Your order price doesn't include the destination country's VAT or duty, so local VAT, customs duties, clearance charges and any courier handling fee are your responsibility when your parcel arrives.
We ship in good faith, but it is your responsibility to check whether the products you order are permitted in your country. With more than 7,000 products, we cannot monitor every local restriction.
3.1b UK Specification: Plugs & Voltage
All our electrical products are UK spec – UK plug, UK 230-240V voltage.
If you're ordering from outside the UK, it's on you to sort out a plug adapter or rewire, and to check your local voltage is compatible. We don't rewire, re-plug, or convert voltage before dispatch, and we're not liable for damage caused by using UK-spec electrical items on an incompatible supply. If you're not sure your setup can take a UK-spec item, check before you order.
3.2 Shipping Costs
Our system is not perfect yet. Standard EU shipping normally starts from around €35, but if the actual cost is higher, we will contact you before dispatch.
You can pay the difference or cancel the order for a full refund.
Want a quote before ordering? Email info@thehydrobros.com, or select bank deposit at checkout so we can review the order before payment.
3.3 How Long Will It Take?
Europe: Usually 2 to 4 working days, although customs can add delays
USA: Surprisingly quick, sometimes around 2 working days
Rest of the world: Usually up to 7 working days or longer, depending on customs
Tracking will be provided as soon as your order leaves us.
3.4 Customs and VAT
International orders may be subject to local VAT, customs duties, clearance charges and additional paperwork.
Please provide a valid email address and phone number so the courier or customs authority can contact you if needed.
Germany is the exception. German orders are sent DDP, so we handle the relevant import charges and you should not be asked to pay anything extra on delivery.
3.5 Temporary EU Customs Duty
From 1 July 2026, the EU introduced a temporary customs duty on qualifying low-value parcels entering the EU from outside the EU.
For consignments with an intrinsic goods value of €150 or less, the duty is generally charged at €3 per customs item or tariff classification, rather than simply €3 per parcel.
For example:
- Several identical products under one tariff classification may attract one €3 charge
- Products under two different tariff classifications may attract two €3 charges
This duty is collected by the courier or destination customs authority when your parcel arrives – not by us at checkout – so it'll show up as part of what's due on delivery, alongside any local VAT.
This measure is temporary because it acts as a bridge while the EU prepares its permanent customs system. It is currently intended to apply until 1 July 2028. After that, low-value goods are expected to move onto the permanent system, where normal customs tariff rates will apply according to the type and origin of each product.
This temporary customs duty is separate from VAT and is also separate from the proposed EU parcel handling fee, which is a different measure.
3.6 What If You Don't Pay Customs Fees?
No payment means no parcel.
If you ignore a customs payment request, the parcel may be delayed, returned or destroyed.
If it is returned to us, your refund will be reduced by:
- Original shipping costs
- Return courier charges
- Any unpaid customs or carrier charges billed back to us
- A 15% administration and restocking fee
If the parcel is destroyed, abandoned or lost because the required charges were not paid, no refund will be issued.
This does not apply to German DDP orders where the relevant charges are being handled by us.
3.6b What If Your Country Won't Let It In?
We'll ship almost anything to almost anywhere – if it fits in a box, we can put a label on it and hand it to the courier. But getting it through customs at the other end is on you.
It's your job to know:
- Whether the product you're ordering is legal to import into your country
- Whether it needs a licence, certificate, or extra paperwork to clear customs
- Whether restrictions apply to that item specifically (voltage, plant nutrients, electricals, batteries, etc. – rules vary wildly by country)
With over 7,000 products shipping worldwide, we can't check every country's import rules for every item – so we don't, and we won't be held responsible for a parcel that gets stopped because it wasn't allowed in, or because customs wanted paperwork you couldn't provide.
If your parcel is delayed, returned, or destroyed because of import restrictions or missing paperwork on your end, the same terms as 3.6 above apply:
- Original shipping costs (non-refundable)
- Return courier charges
- Any customs or carrier fees billed back to us
- A 15% admin/restocking fee
If it's abandoned or destroyed rather than returned, no refund will be issued.
Not sure if something can legally land in your country? Check with your own customs authority before you order – not after it gets stuck.
3.7 Faulty Products
For overseas orders, you're responsible for the shipping costs of any return, repair, or replacement – including if the item is faulty – unless we've confirmed otherwise with you in writing.
3.8 International Summary
For most international destinations, customs rules, local taxes, duties and paperwork are your responsibility.
For Germany, we are VAT registered and ship DDP, so there should be nothing extra to pay when your parcel arrives.
For qualifying EU consignments worth €150 or less, a temporary customs duty may apply on delivery. This is normally calculated at €3 per customs item or tariff classification, and is collected by the courier or customs authority – not by us at checkout.
Check before buying if you are unsure. It saves everyone a headache.
Returns
Thank you for shopping with The Hydro Bros. We hope you're happy with your purchase — but if you've changed your mind, ordered the wrong item, or need to return something, here's how it works.
How long do I have to return something?
You have 14 working days from the day your order is delivered to request a return. All returns must meet the following conditions to be accepted.
What are the return conditions?
To be eligible for a return:
The item must be unopened, unused, and in original condition
All packaging must be intact, including outer boxes and security seals
The product must be returned in "box-fresh" condition — clean, untorn, and free from tape, labels, or writing
Faulty items must be returned in full for inspection
Returns are only accepted from end consumers, not businesses purchasing for resale
Returns must be authorised by us before sending anything back — contact info@thehydrobros.com
Who pays for return shipping?
If the item is not faulty, you are responsible for the return shipping costs.
We recommend using a tracked and insured service — the item remains your responsibility until it arrives back with us.
What if I reject the delivery or miss it?
If you refuse delivery or fail to collect your parcel and it gets returned to us, we'll offer to resend or refund:
Resend — the reship fee is whatever you paid for shipping originally. If your original order had free shipping, we'll calculate the reship cost based on what it actually costs to send it again. Pallet items start from £60, and can be more for remote areas (Highlands, Islands, NI, etc.).
Refund instead — minus the original delivery cost, reship/return costs, and a 15% restocking and handling fee.
Full detail on missed and failed deliveries is on our Shipping Policy.
Will I get a full refund?
If your return is accepted, we'll issue a refund minus:
The original delivery cost (even if not listed separately at checkout)
A 15% restocking and handling fee
These fees help cover the cost of inspection, repackaging, and processing — returns aren't free to manage, and this keeps pricing fair for all customers.
Why do you charge a restocking fee?
Hydroponic gear often requires careful inspection, cleaning, and handling to be resold safely. The 15% restocking fee helps cover these operational costs and allows us to continue offering competitive prices across the board.
What if my item is faulty?
If you believe an item is faulty, contact us first with photos/videos to verify the issue. If confirmed, we'll guide you through the return process and offer a like-for-like replacement.
If the item is returned and found to be fully functional, the return will be treated as a standard one — and all standard fees will apply (delivery + 15%).
For orders shipped outside the UK, you're responsible for the shipping costs of any return, repair, or replacement — including if the item is faulty — unless we've confirmed otherwise with you in writing. See our Shipping Policy for international shipping details.
What happens if I return something in poor condition?
If the item is:
Used,
Damaged,
Missing parts, or
Returned with torn, marked, or taped-up packaging,
We reserve the right to refuse the refund entirely.
You'll then have two options:
Arrange return shipping at your own cost
Leave the item with us — if unclaimed after 28 days, we will responsibly dispose of it
Cancellations
Can I cancel my order?
Yes. Under UK distance selling rules, you have 14 days after receiving your order to cancel it entirely. The same return conditions as above apply — unopened, unused, original packaging, box-fresh.
What if I cancel after it's already shipped?
You'll get a refund once we receive the item back, minus the cost of shipping and a 15% admin fee.
What if the returned item isn't in as-supplied condition?
If it's been opened, used, or marked, we reserve the right to treat it as a partial loss and refund a clearance value rather than the full amount paid.
Damages & Receiving Your Order
What should I do when my parcel arrives?
Inspect it for damage before you sign for it. If there's any sign of damage, tell the courier in writing at the point of signing — and keep all packaging in case you need to make a claim.
What if I sign for it without mentioning damage?
We can't accept a damage claim for a parcel you've signed for without noting damage at the time. Once signed for, any damage found afterwards is treated as having happened after delivery.
What if something's missing from my order, or the wrong item's inside, or it's damaged in transit?
Open your parcel and check the contents as soon as it arrives. You need to report transit damage, missing items, or wrong items within 24 hours of delivery.
We get contacted weeks — sometimes months — after delivery by people who never opened the box, saying an item's missing or damaged. We can't do anything with that. No packaging, no timely report, no proof it didn't happen after the fact — there's nothing to investigate and nothing we can action. Check your order when it lands, not when you finally get round to using it.
What if an item develops a fault later on?
That's a different situation to transit damage — see the Faulty Items section above. There's no 24-hour cutoff for genuine faults; contact us with photos/videos when the issue shows up and we'll take it from there.
What if my order doesn't arrive when expected?
Let us know within 2 days of the expected delivery date — that gives us the best chance of sorting it.
What if my parcel goes missing entirely?
You must tell us in writing within 7 days of the expected delivery date. Couriers have a claim window, so if we're not told in time, we can't make a claim and can't refund the loss.
Are damage claims accepted for items caused by misuse or abuse?
No — we don't accept return or damage claims resulting from physical damage or abuse after delivery.
Lost Parcels
What happens if my parcel goes missing?
We'll open an investigation and claim with the courier. You'll need to participate — this may include completing and signing a legal declaration form to support the claim.
How long does this take?
Once the claim is approved, a refund can take up to 10 working days to process.
Refund Timing
How will I know if my refund is approved?
We'll notify you once we've received and inspected your return, and confirm whether it's been approved.
How do I get paid back?
Approved refunds go back to your original payment method automatically, minus any deductions covered elsewhere on this page (shipping costs on non-fault returns/cancellations, restocking fees, condition deductions).
How long does it take to arrive?
Please allow 10 working days from refund confirmation for the money to actually land back with you — your bank or card provider can add extra processing time on their end.
Over 15,000 Customers
Growers across the UK have ordered from us since 2019.
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