Best CO2 Generators and Controllers: 2026 Buying Guide

Sensor, display and switching in one box: connect a regulator or burner, set a level and it learns your room.

• Built-in CO2 sensor
• Self-learning auto-tune
• Regulator or burner
• 4A (960W) output

• Intelligent dose eases off as the level nears your target, so it does not overshoot
• Keeps its settings with the power off, so it can run from the lighting timer and dose only in the light period

Know before you buyBottled CO2 needs a solenoid regulator, such as the Pro-Leaf CO2 Regulator. Allow a few days for it to learn the room before fine-tuning.

The controller that switches the Pro-Leaf LPG generator, and it runs a CO2 bottle just as well.

• 400–2,000 ppm
• Bottle or propane
• Day and night mode
• 1-year warranty

• Doses in short bursts, which stops a bottle regulator sticking open when cold
• CO2 disable mode runs an extractor to pull levels down in a closed room

Know before you buyThe sensor calibrates itself, but a manual calibration once a year is worth doing. For bottled CO2, add the matching Pro-Leaf CO2 Regulator.

Burns propane to make CO2 in bulk for large sealed rooms.

• 4, 8 or 10 burners
• 0.30–0.75 m³/h CO2
• 3–6.65kW heat
• Electronic ignition

• Burner plugs trim the output for a smaller room; the 10 burner can also run 2, 5 or 7
• Solenoid valve shuts the gas if the burners fail to light; a tip-over switch cuts the power

Know before you buyBurning propane also gives off heat and water vapour (6kW of heat from the 8 burner), so plan cooling and humidity around it. It needs a CO2 controller; fit a carbon monoxide alarm.

A room controller that stage-doses bottled CO2 or a gas burner, works with your extraction, and takes an analyser when you want ppm control.

• Multi-stage dosing
• Bottle, propane or natural gas
• Fan control
• Day/night sensor

• The matching Ecotechnics regulator, with gauge and solenoid, is the Regulator Only option
• A burner connects straight to the controller with no regulator

Know before you buyThe NDIR analyser that lets it read and hold an exact ppm is not included. Without it, the controller works from an external thermostat or hygrostat.

Measured bursts of CO2 from a small can, with no bottle, regulator or mains lead in the tent.

• Battery powered
• Light sensor
• 1–3 sprays per cycle
• 60 g can included

• Intervals from 5 minutes to 4 hours, set from the remote
• Aims a small to medium tent at around 1,200 ppm and adds no heat

Know before you buyIt runs on a timer, not a reading, so it cannot hold a set level. A can lasts 1–4 weeks depending on tent size and settings; the refill is the AirBomz Maxi Plus can.

Add a litre of tap water, shake, and it releases CO2 for around three weeks with nothing to plug in.

• Water-activated
• About 3 weeks
• Tents up to 1.2 x 1.2 x 1.2 m
• Hang or stand

• No bottle, regulator, controller or power
• Hangs from the tent frame above the canopy, so the CO2 falls through the plants

Know before you buyThere is no control: it cannot reach a set level or be switched off. It does most in a closed or slow-extraction tent, where the CO2 is not pulled straight out.

An independent NDIR monitor with an audible alarm: the second check every enriched room needs.

• NDIR sensor
• CO2, temperature, RH
• Audible alarm
• 24-hour chart

• Backlight turns green, amber or red as CO2 rises
• USB powered from the supplied adaptor, a PC or a power bank

Know before you buyIt reads and warns but switches nothing, so it sits alongside a controller, never in place of one. Set the alarm threshold before you start enriching.