Best Dehumidifiers for Grow Rooms: 2026 Buying Guide

The right size for most grow rooms, and rated honestly: 20 litres a day on the box, 10 at normal room conditions.

• 20 litres/day at 30°C, 80%
• 10 litres/day at 27°C, 60%
• 41 dB(A) quiet mode
• R290 refrigerant

• Set a target RH and it cycles to hold it
• Continuous drain, or a 4.3 litre tank with a full-tank cut-off
• Draws 280–330W

Know before you buyIt needs a room of at least 4m² and 30cm clear of walls, so it does not belong inside a small tent. It weighs 13.5kg.

Sized for a tent and rated on a realistic draw: about 4 litres a day from the Hydrone 5.

• About 4 litres/day
• Tents up to 1.5m²
• Twin 15cm duct ports
• Down to 25% RH

• Sits in the tent, or outside it and ducted in
• Ten drying levels; pairs with AC Infinity controllers
• Hydrone 7: up to 3m², about 8 litres a day

Know before you buyIt draws 209–350W, so it adds noticeable heat, and the 2 litre tank needs emptying often without the drain.

The most capacity for the money: twice the 20L’s rating for £30 more.

• 40 litres/day
• Rooms of 30–40m²
• 530W
• 4 litre tank or drain

• Holds a set RH, with a 0–24 hour timer
• Full-tank alarm, castors and handles
• Clear sizing: 12L for 15m², 20L for 20m², 40L for 30–40m²

Know before you buyThe 40L is the loudest of the three, rated under 53 dB, and at 530W it warms the room.

For tents and small rooms run from the VIVOSUN app: it reads VPD at canopy height and dries to hold your target.

• Up to 12 litres/day
• VPD probe
• App control
• 185W

• Rated at 42 dBA or lower
• 2.1 litre tank with a full cut-off, or a continuous gravity drain

Know before you buyYou pay for the smart features. Without the VIVOSUN app, the RAM 20L removes more water for less money.

Up to 60 litres a day for a large room full of plants.

• Up to 60 litres/day
• 650W
• 6 litre tank or drain
• Dual-speed fans

• Runs continuously, or stops at your target RH
• Timer and sleep mode to focus drying on lights-off
• Handles and castors

Know before you buyAt 650W it gives off real heat, so plan the room’s cooling around it.

For commercial and multi-room set-ups: a built-in pump and a remote control, so it can live out of the way.

• 65 litres/day at 30°C, 80%
• 32 litres/day at 26°C, 60%
• 520W
• Pumps water up 3m

• Remote controller on a Cat 5 cable, with its own humidistat
• Rated under 50 dBA

Know before you buyIt weighs 23.5kg and costs serious money. It only makes sense where you would otherwise need two smaller units.