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Need For Speed Control – Fan Speed Controllers

Without close control of fan speeds the effectiveness of your ventilation system may suffer. The simple addition of a controller will help you to optimise the growing environment and improve results – take a look at our review of the very best models around.
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GroWell Team

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Here's a quick recap on the reasons for using an extraction system...


The Importance of Ventilation

Regularly extracting and replacing air in your grow room has a significant and positive impact upon your plants. They need this constant supply of fresh air to replenish CO2 and oxygen levels and maintain healthy temperatures. A good ventilation system also helps to minimise the risk of damp and mould and let’s you more closely manage grow room humidity.


All you need to set up an extraction/filtration system is the following:

- A good fan (e.g. an Lti Systemair RVK Extractor Fan or an Isomax Acoustic Fan)

- A matching Carbon Filter

- The relevant Ducting, Quick Release Clips and/or Fast Clamps plus hanging accessories from which to suspend it

Extraction System Alternatively, you could just opt for a Complete Extraction/Filtration Kit that includes each and every required component.


Fan Limitations

Although you may have the fan(s) for the job, manually finding the optimum fan speed is very difficult - especially during summer when temperatures tend to change a lot between day and night. Your fan(s) alone won’t respond to such fluctuations, reducing their overall effectiveness and in the worse case scenarios restricting plant growth.


Fortunately a solution does exist...


Fantastic Fan Speed Controllers

Fan speed controllers allow you to adjust the level of extraction and/or intake in accordance to grow room conditions. There are currently a number of excellent models available to choose from, accounting for a variety of factors and the demands of different growers – just make sure you don’t go without one!


So, what do we consider to be the "BIG 3" fan speed controllers? Let's find out!

Fan Speed Controller

Variispeed Fan Controller

The Variispeed Fan Controller is perfect if you're only using a small extractor fan and need a low-cost option for manually adjusting the speeds.


+ Simple controls (just twist the dial to alter the speed)

+ Accommodates a maximum power load of 300W (200mm/8 inch fan)

+ Ideal for beginners with a one light set up

Variispeed Fan Controller

Code Price Qty
Variispeed Fan Controller 2479 Variispeed Fan Controller


SMSCom 4.5 Amp Twin Fan Speed Controller Mk2

To control your temperature with the speed of your fans, you need an SMSCom 4.5 Amp Twin Fan Speed Controller. Simply set your target temperature  - fans  then speed up if your room needs cooling, or slow down if it needs heating. To make sure enough air is exchanged, you can set a minimum and maximum fan speed. They're easy to use - everything is plug & play.


+ No hardwiring needed - plug & play design

+ Inbuilt temperature sensor

+ Minimum & maximum fan speeds for safety

+ IEC power cable connection

+ Replaceable 4.5 Amp fuse

SMSCom Twin Fan Speed Controller

Code Price Qty
SMSCom 4.5 Amp Twin Fan Speed Controller Mk2 3891 SMSCom 4.5 Amp Twin Fan Speed Controller Mk2


GSE Temperature & Negative Pressure Fan Speed Controller

This smart GSE device manages the airflow of your fans to establish and maintain the preferred grow room temperature. It also provides a negative pressure setting that helps stop unwanted smells from escaping the plant-growing environment. Use with an intake and extractor fan of the same size.


+ Select target temperature, minimum fan speed and negative pressure balance

+ No noise produced by the unit or the fans

+ Easy-to-use dimmer style controls

+ Includes a digital temperature sensor on a 4-metre cable

+ Water resistant casing with splash protection covers for the sockets

GSE Controller

Code Price Qty
GSE Temperature and Negative Pressure Controller 2050 GSE Temperature and Negative Pressure Controller


If you would like to learn more about these products or discover the many others that are available, click here or speak to us - you can either leave a message below, start an instant chat or pick up the phone and call 0333 003 22 96.

This post was posted in Buyers Guides, Fans, Filters & Environment, New Growers, Ventilation and was tagged with air, Carbon Dioxide, control, environment, extraction, fans, filtration, humidity, Oxygen, temperature, ventilation


2 Comments - Add Comment

  • Allan Gray
    Posted March 1, 2016 at 9:29 pm
    I need a fan controller. Can you tell me if the GSE Temperature and Negative Pressure Controller controls the fan by altering the current or voltage?

    Kind Regards,

    Allan Gray
    • Replies

    • GroWell Team
      Posted March 8, 2016 at 2:25 pm
      Hi Allan, the GSE Temperatue and Negative Pressure Comtroller is a resistive controller. The GSE Step Tranformer is a voltage controller.

      Hope this helps
      Growell Team
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