Professional Humidifiers

Professional Humidifiers

from £299.00

Midi Centrifugal Humidifier

Increase Quantity Decrease Quantity

Midi Complete Humidity Kit

Increase Quantity Decrease Quantity

Maxi Centrifugal Humidifier

Increase Quantity Decrease Quantity

Maxi Complete Humidity Kit

Increase Quantity Decrease Quantity


The Myth: Plants hate high humidity levels.

The Truth: Plants thrive when there's high humidity during propagation & veg!! To improve nutrient uptake, transpiration, cell division & fruit/bud development, aim for 70 – 85% (propagation), 65 – 75% (vegging) or 45 – 65% (flowering)

Want a quick, easy & affordable way of boosting yields? Try a Professional Centrifugal Humidifier!

They humidify large areas quickly on just 90W…that’s incredible!

On that power, you get a humidification capacity of 2,500cc to 4,000cc per hour (Maxi) or 1,500cc/hour (Midi).

Don’t worry about space – they’re tiny! You can install them in minutes.

To control the direction of your humidifier’s fog – simply use the removable fogging head.

They’re perfect in a 10 – 15 light room (Maxi) or a 4 – 6 light room (Midi) – you can use them during propagation, too.

Buy the humidifier and water tank separately, or opt for a complete humidity kit which comes with a 100 Litre Space Sava reservoir and pipework.

• Supplied with a humidity meter
Simple to fit (connects to taps & tanks)
Easy to carry by handle
• Connects to any water reservoir for automatic top-up
Suitable for propagation
Low energy – just 90W
• Control! Removable fogging head included
• Coverage 15-30m² (Midi)  or 100-150m² (Maxi)
• Humidification Capacity: 1,500cc per hour (Midi) or 2,500cc / 4,000 cc per hour (Maxi)
Compact – 31cm x 31cm x 47cm (Midi) or 37cm x 37cm x 48cm (Maxi)

We Recommend

Always use filtered water with your humidifier. Otherwise, mineral deposits will build up on your reflectors and lamps. They'll also clog up carbon filters.

After 3 months of using hard water with your humidifier, you’ll lose up to 10% of reflectivity – that’s around a 5% loss in yield!

To prevent this from happening, use an RO water filter.


Midi Centrifugal Humidifier:
• For 4 – 6 light rooms / 15 - 30m2
• Humidifier only

Midi Complete Humidity Kit
• For 4 – 6 light rooms / 15 - 30m2
• Includes 100 Litre Space Sava reservoir + pipework

Maxi Centrifugal Humidifier
• For 10 – 15 light rooms / 100 and 150m²
• Humidifier only

Maxi Complete Humidity Kit
• For 10 - 15 light rooms / 100 and 150m²
• Includes 100 Litre Space Sava reservoir + pipework


The Science

What’s Humidity?

Your humidity level tells you how much water vapour your air holds.

To measure your humidity, you need to take an RH (relative humidity) reading.

Your relative humidity is a percentage (%) of the maximum amount of water your air can hold.

If you get a relative humidity reading of 100% RH, your air will not be able to hold onto any more water – unless your temperature increases (the warmer the air, the more water it can hold onto).

The Big Myth

A lot of growers aim for a low humidity level. This is to ward off potential pathogens.

However, these pathogens aren’t really a threat until flowering – you’re far better of aiming for a higher humidity during propagation (70– 85% RH) and veg (65 – 75% RH).

You can them lower your humidity during flowering (45 – 65% RH) to ward off pathogens.

Why Do Plants Like High Humidity?

It’s important that plants stay hydrated to absorb and transport nutrients.

In a low humidity environment, water leaves your plant (transpiration) at a faster rate. Plants can end up losing too much water.

This is because:

• The humidity inside plants is around 100%.
• Water moves from areas of high humidity to areas of low humidity
• The bigger the difference in RH, the faster this happens

Sound confusing?

Think of ice cubes – it’s the same principle but with heat.

• They melt when you put them in a drink
- because heat moves from high concentrations to low concentrations.

• They melt faster if you put them in a hotter drink
- because there is a bigger difference in temperature.

Water works the same way...  

The lower your grow room humidity, the greater the rate of transpiration.

Recommended Humidity Levels

• Propagation: 70– 85% RH
A high humidity makes it easier for plants to stay hydrated - they have more energy for rooting & growth.

• Veg: 65 – 75% RH
Plants quickly start developing leaves and shoots – this slows transpiration down. If there’s not enough transpiration, your plants won’t be able to absorb enough water and nutrients.

• Flowering: 45 – 65% RH
To counter the risk of rot, your humidity needs to be lower during flowering. A good ventilation system will help keep your humidity down.

During night (or ‘lights off’), your RH should be 10% lower.

Kit Contains


Centrifugal Humidifier Kits:

1x Centrifugal Humidifier complete with hygrostat
1x Space Sava Water Butt - 100 Litres
1x Space Sava Water Butt Stand
5x 13mm Flexi-Pipe (metre)
1x 13mm In-Line Filter
1x Continental Plug Adapter - 3 pin/2 pin

How to Use

Full, illustrated GroWell instructions are supplied with your humidifier.

1. Put your humidifier on a flat surface
- If there’s little or no ventilation, put it in a central location

2. Connect a water supply to the 6mm female inlet

3. Plug it straight into an electrical outlet for evaluation

4. After evaluation, plug it:
- into a sensor for automatic control
- into a timer for specific automatic interval control
- directly to an electrical supply for manual use

5. Operation
- Use the fogging head for directional fogging output
- Operate without fogging head and the fog will propel 4 -5 feet above the unit


Q & A

Questions and Answers (1)

Hi can you tell me what the operating noise level in dB is please, and does this unit send out cool air or hot air?
We have checked the instructions for these humidifiers, there isn't a dB level listed, however, they make around the same amount of noise as a small extractor fan. These units put out a cool mist.

Written by BK | 28 Sep 2011