Growroom ventilation

The importance of proper grow room ventilation, by Gweedo

Good ventilation is very important when growing crops in an enclosed space. Not only for the plants themselves, but with the right installation you also grow safely, efficiently and prevent nuisance from odor and noise. In this blog we will tell you which equipment you need for good grow room ventilation and what you should pay attention to when purchasing an exhaust fan.

Grow room ventilation


The exhaust installation system

An exhaust fan extracts air from the grow room. The extraction creates a negative pressure in the room and fresh air is sucked in through the ventilation openings. The plant extracts carbon dioxide, CO2, from this fresh air. The plant needs CO2 to convert light into oxygen and sugars that serve as food for the plant. This process is called photosynthesis.

Exhaust fans

In principle, there are extractors with three different types of fans. The suitable fan is selected depending on the application and the amount of air to be moved.

1. Axial fans

With these fans, a propeller moves the airflow in a horizontal direction. They can move a relatively large amount of air, but with a pressure range of 80 Pa, they can only do this when no suction or discharge power is required.


Axial ventilator

Axial fan

2. Diagonal fans

These are further developed axial fans with a higher efficiency. The air blades are conical and aerodynamically shaped so that the airflow from the fan is expelled at an angle of 45° to the inlet. They can be used up to a pressure range of 250 Pa.

diagonaal ventilatorDiagonal fan with conical and aerodynamically shaped blades

3. Radial fans

These fans have turbine-like impellers that suck in air horizontally and expel it vertically. With a pressure range of up to 1000 Pa, it is the most efficient solution for moving large volumes of air with high filter performance.

Grow room ventilation

Radial fan with back wards curved impellers

G-tools extractors have diagonal fans. These encounter little resistance on the suction and discharge side. With their large air displacement and high efficiency, they are ideal for the G-tools grow cabinets. The extractors are equipped with two types of motors, AC and EC motors.

AC engine

The Alternating Current motor is a conventional alternating current motor. The housing of the AC motor, the stator, contains permanent magnets. In the rotating part, the rotor, an alternating electromagnetic field is generated that opposes the magnetic field of the stator. As a result, electrical energy is converted into a rotating movement. The speed of the AC motor depends on the frequency and the voltage. Connected directly to mains voltage, the fan motor runs at its maximum rotational speed. To control the speed of the motor, the voltage or frequency must be adjusted. In most cases this is done by adjusting the voltage with a variable adjustable transformer, or dimmer. The disadvantage of this is the large power loss that results in heat generation and humming noises in the dimmer and the fan. Another disadvantage is that the permanent magnets in the housing have a braking effect on the rotor when it moves in an area where the magnetic field is not optimal.

EC engine

The technique of the Electronically Commutated motor is described as “soft communication”. This is the combination of communication strategy and engine design. In this case, there are several permanent magnets in the rotating part, the rotor. The stationary part, the stator, contains electromagnets that are controlled by intelligent electronics. The electrical energy is converted into a rotating movement of the rotor. Sensors measure the speed and position of the propeller. As a result, the engine always runs in the most efficient way with the highest possible power range. Thanks to the electronics in the motor, the fan speed can be adjusted steplessly without loss of power and noise. Another advantage is that the EC motor can be connected to both a direct current and an alternating current network. The EC motor is barely larger than an AC motor and fits in the same housing. With the same size, an EC extractor delivers better performance with lower consumption. The G-tools extractors are plug-and-play, so it is very easy to upgrade from an AC extractor to a more efficient EC extractor.

What should you pay attention to when purchasing an extractor

To choose the right extractor fan, calculate the volume of the room and compare this with the capacity of the extractor. An extractor that is too large makes unnecessary noise and wastes energy. With an extractor that is too small, the plants do not get enough fresh air and they will lag behind in growth and flowering. The type and wattage of the lamp you use are also important when purchasing an extractor. If you want to benefit from a strong lamp, you will also have to supply a lot of fresh air and dissipate a lot of heat.

Calculate the capacity of the fan

For flowering plants with high intensity lighting, it is ideal to refresh the contents of the grow room three times per minute.

As an example we take the Bonanza (1mᒾ) with 2x G-bars 170W Led.

This grow box has a capacity of 1.62 m3. To move this volume 3 times, you need at least a fan that can extract 3 x 1.62m3 = 4.86m3 in one minute.
The capacity, or flow rate, of an exhaust fan is always stated in cubic meters per hour. So 4.86m3 x 60min. = 292m3/hour.

The complete kit contains the G-tools 125 tube fan with 2 settings. The first position is ideal in the beginning of the grow. The young plants use little CO2 and you grow more economically. The high position is perfect for a good flowering phase.

Other factors will affect system performance during operation. If the air system has many bends and a silencer is fitted, extra resistance will arise on the discharge side. The filters become dirty over time, which reduces the suction power on the inlet side of the fan. The displacement of the amount of air is strongly dependent on these resistances.

Good ventilation is a good climate

The right temperature and humidity are of great importance for the growth and flowering of the plant. Running the exhaust fan more slowly or faster has an effect on the climate in the cabinet. If the speed of your exhaust fan cannot be controlled, a fan controller is recommended to automatically control the speed of the breeding fan and thus manage the climate in the cabinet. With a clip fan you create even better air circulation in the cabinet. In addition, the airflow moves the plant, making it firmer and stronger.

Grow room ventilation

The G-tools 125- 2 speed fan connected to the suction side with a Prima Klima eco filter

Prevent odor nuisance!

With a good installation you ensure that no odor escapes from your grow room. This way you prevent odor nuisance and keep your cabinet neatly hidden. Therefore, always connect a carbon filter to your extractor. You can choose from an Eco filter or an Industry filter. When purchasing, pay attention to the capacity of the filter and match it to the extractor. (With a filter that is too large, the contact time is too long and the carbon does not filter the pollution out of the air) or (A filter that is too large is unnecessary). If the filter is too small, it will slow down the exhaust fan, causing it to consume much more energy. The contact time is then short and the air is not properly filtered. Keep the filter clean and replace it in time, this prevents unnecessary load on the fan and keeps the electricity costs lower.

Do you have any questions about the importance of good breeding ventilation? Please feel free to contact us.