Best CO2 generators for grow rooms and greenhouses: Boost plant growth
To grow, plants require the carbon dioxide (CO₂) of the air, but its availability can run out quickly in closed grow rooms or greenhouses. When the air isn’t replaced often, CO₂ levels fall, and plants can’t grow properly, despite enough water and light. That’s a frequent problem in indoor growing environments, such as rooms with sealed windows and no fresh air circulation, because plants need carbon dioxide (CO₂) to thrive properly, but without a good supply of CO₂, plants grow more slowly, producing smaller harvests.
Many growers solve this issue by using CO₂ generators. The machines increase the amount of CO₂ in the air, and this in turn helps plants grow better and faster. By using a generator, they can increase the CO₂ amount from its natural amount of 400 parts per million (ppm) to 800–1,500 ppm, the optimal CO₂ range to grow better. This encourages bigger and stronger plants and helps produce better quality flowers that are richer in flavor and yield. In recent times, greenhouse CO2 systems have become common place in small grow rooms and on a larger scale, greenhouse units.
Types of CO2 Generators
There are a variety of CO₂ generators available for boosting CO₂ in grow rooms and greenhouses. Each works in its own way and is appropriate for different sizes of space.
1. Propane-Powered Generators
Propane CO2 generator reviews state that its function are burning propane gas to produce the carbon dioxide. When 1 pound of propane is burned, approximately 3 pounds of CO₂ are emitted. These are popular in grow rooms because they constantly release CO₂.
They’re available in different sizes, including models with 4 or 8 brass burners, depending on how much CO₂ is required. They also generate lots of heat, which might be good in cold climates, but not so good in hot ones.
2. Natural Gas Generators
Natural gas generators operate similarly to those using propane but use natural gas. Among the biggest advantages is that natural gas is frequently cheaper and can be hooked up to a gas line, so there’s no risk of running out. That makes them perfect for ample greenhouses or commercial growers. They are also more convenient to maintain as no tanks need refilling. However, natural gas generators also generate heat and must be properly ventilated to be used safely.
3. Electronic CO₂ Generators
Non-electric CO₂ systems do not utilize fuel burning. Rather, they are powered by compressed CO₂ gas in tanks. These are attached to regulators and emitters that shoot little puffs of CO₂ into the atmosphere as they’re required. The process is clean and quiet, with no heat or flames required.
It is perfect for small indoor grows or places where heat is a concern. Other growers occasionally rely on cheap DIY methods, such as CO₂ bags or sugar-and-yeast mixtures, which are sufficient only for very small grow tents and not very reliable.
Comparing Performance Metrics
If selecting a CO₂ generator, make sure to find out about how well it works. Factors include how much CO₂ is produced, how much heat is generated and how easily the systems are controlled.
CO₂ Production Rate
Not all CO₂ generators produce the same quantity of gas. Propane and natural gas models most often indicate their flow rates in cubic feet per hour (ft³/hr) or pounds per hour(lb/hr). There's more CO₂ coming from the bigger setups and those larger models might be perfect for big grow rooms.
CO₂ tanks, on the other hand, expel gas in controlled spurts. Tanks may be more consistent over time, as pressure drops, but they deliver less cleanly. Burners only release a continuous stream of CO₂ for so long, with fuel depletion serving as a natural limiter.
Heat Generation and Management
One significant drawbacks of generators that need fuel is they generate heat. This excess heat can heat up a grow room even more, causing potential damage to plants if not properly controlled. That heat is expressed in BTUs (British Thermal Units) and high-output generators can put out a lot of it.
To deal with this, processors may require good ventilation systems, air conditioners or exhaust fans to regulate temperatures. Electronic CO₂ tanks do not produce heat, making them more appropriate for heat-sensitive environments.
Control and Automation
Today’s CO2 generators have great options built-in that are helpful for the grower. Some are equipped with electronic ignition to light the burner automatically, though older versions might have pilot lights that remain on all the time. User can also control CO₂ levels by using environmental controllers or timers or sensors.
These devices monitor the CO₂ level and keep it at the proper level all day long without requiring any further attention. By automatically maintaining conditions, users save time and help the plants grow better.
Sizing and Installation
It’s important to select the correct size for the space and to install the CO₂ generator properly in order to get the maximum benefit from it. This keeps plants at optimal CO₂ levels, with nothing wasted and without compromising safety.
Calculating CO₂ Needs
The first step is to determine how much CO₂ is required. Farmers are armed with a simple equation:
Room volume (in cubic feet) × desired ppm increase ÷ 1,000 = CO₂ in cubic feet
For example, a grow room of 200 square feet with an 8-foot ceiling has a volume of 1,600 cubic feet. If one were to want to get to 1,000 ppm in this case, this calculation would instead be:
1,600 × 1,000 ÷ 1,000,000 = 1.6 ft³ of CO₂
This shows how much gas is needed to raise the CO₂ level in the room. Using this number, growers can choose a generator or tank system that matches the space size.
Placement and Distribution
The location of the CO₂ generator or tank emitter, for instance, can impact how uniformly the CO₂ is distributed throughout the room. Burners must be installed at the right height, typically a bit above plant level, and in a location where air flow aids in distributing the CO₂. With larger areas, it would be better to use a number of smaller CO2 emitters rather than one large CO2 generator for grow tent to achieve more even coverage. With good circulation from fans, CO₂ is spread evenly to maximize all plants.
Ventilation and Sealing
To maintain consistent levels of CO₂, the grow area needs to be tightly sealed. That means by utilizing tight door seals and regulating airflow. Negative pressure rooms (air being pulled in) can lose CO₂ rather quick, so a balanced or even slightly positive pressure is preferable. Ventilation systems should be regulated so as to not waste CO₂. It’s also necessary to have emergency purge systems, fans or alarms that can extract CO₂ rapidly if levels rise too high, for safety.
Best CO₂ Generators for Grow Rooms and Greenhouses
Here are 5 of the most popular CO₂ generators available to help farmers pick the right one. They come in different sizes, capacities and fuel sources, such as Propane (LP), natural gas (NG) and a refillable CO₂ system.
1. CO2 Generator 12‑Burners NG – The Protector
The Protector is a commercial blueprint for a natural gas generator built for space in large commercial greenhouses and big grow rooms. It operates with twelve brass burners, generating some 32 cu ft of CO₂ per hour (equaling some 2.7 cu ft per burner). It’s fed directly from a natural‑gas line, ensuring a continuous worry‑free supply of CO₂, without tank changes.
Room temperatures can be raised significantly by the heat of combustion, so it is best suited to installations with strong climate control. It is ideally suited to spaces in excess of 1,000ft² where even CO₂ distribution is essential.
- Direct connection to the natural gas line for constant supply.
- 12 brass burners which are to produce about ~2.7 cuft/hr.
- Built‑in flame safety shutoff valve and flame sensor.
- Ideal for spaces of 1,000ft²+ with good airflow.
2. HydroGEN PRO Water‑Cooled CO2 Generator, LP
The HydroGENPRO is powered by liquid propane (LP) and devoid of natural gas or air heat exchangers; four brass burners produce approximately 12cuft of CO₂ per hour. Its most powerful asset is its water-cooled heat exchanger which extracts 86% of the heat created from combustion before it is expelled into the grow environment.
This helps to stabilize room temperatures and makes it ideal for crops that are sensitive to the climate and warmer climates. Electronic ignition is a standard and reliable start‑up that does not require a pilot light, and LED indicators help troubleshoot any issues. It is ideal for mid‑sized grow rooms, with a surface area between 300ft² and 600ft², where the excess heat would put too much stress on air‑conditioning.
- Four brass burners generating ~12 cu ft/hr CO₂.
- Water‑cooled exchanger reduces heat up to 86%.
- The electronic ignition and all other controls seamlessly integrate into this aesthetically pleasing design that has high-visibility LED status lights.
- Perfect for keeping small rooms up to 300-600 sq. feet cool and comfortable.
3. LTL Controls CO2 Generator 10‑Burners NG (High Altitude)
This high‑altitude model is from LTL Controls and is designed for growers at elevations of 5,000ft or higher. It turns ten brass burners to deliver about 27 cu ft of CO₂ per hour. The air‑fuel mixture is factory‑preset to provide efficient combustion in thin mountain air, thereby minimizing the potential for incomplete burning and carbon monoxide generation.
It runs on a gas line, like other NG models, for endless fuel. It is well suited to greenhouses or indoor farms in mountainous regions, where it is necessary to enrich CO₂ and run under low air pressure.
- Ten brass burners, ~27 cu ft/hr output.
- Tuned for elevations above 5,000 ft to ensure clean combustion.
- Direct‑connect natural‑gas operation.
- Fits mid‑to‑large spaces (500–1,200 ft²) in high‑altitude settings.
4. TNB Refill Pack Natural CO2 Generator
The TNB Refill Pack is not a burner, but an inert refillable CO₂ cartridge system. It uses an on-off gas pulse with a regulator, gas solenoid valve, enabling the grower to produce anything from 0.5cuft to 2cuft gas per hour.
No flame and incredibly safe to use in small grow tents and hobby setups ( Up to 100ft²). Cartridge refills are simple and economical for low‑volume users. But it offers no high throughput for bigger jobs and is adjustable for pressure.
- Pulse‑release equipment with variable flow (0.5–2 cuft/hr).
- No heat and no open flame, very safe in a small space.
- Cartridge refillable at gas stations specializing in camping gas.
- Perfect for grow tents or small hobby gardens up to 100ft².
5. Titan Controls Ares 4 – Four‑Burner LP CO2 Generator
The Titan Controls Ares4 is a middle‑of‑the‑road LP generator and it's offered in NG as well. This includes four brass burners at 10.6cuft/hr on propane (10.8cuft/hr on natural gas). The solid‑state electronic ignition requires no pilot light, and works with CO₂ controllers and timers.
It comes with a regulator, hose, hanging chain, ceiling hook and power supply for easy installation. It is designed for grow rooms up to 500ft² and provides accurate and efficient CO₂ without the need to manage additional heat loads.
- Four brass burners, 10.6 cu ft/hr (LP) or 10.8 cu ft/hr (NG).
- Electronic ignition—no pilot light required.
- Complete kit: regulator, hose, hanging kit, power supply.
- Ideal for 200–500 ft² grow rooms.
Safety Considerations
It’s important to safely control the greenhouse CO2 system for own safety and the safety of any other plants and people inside the grow room too. Appropriate safety measures prevent accident and continue to keep the air safe for breathing.
Combustion By-Products
Products of combustion like CO (carbon monoxide) and NOx (nitrogen oxide) can be generated from propane or natural gas generators. These gases are dangerous if left in place. To keep air quality safe, those gases should be monitored using detectors. By putting CO alarms and NOₓ sensors in the grow room, user can monitor dangerous levels before they become an issue. Periodic testing of the air quality should be included as part of an ongoing maintenance schedule for any safe atmosphere.
Fire and Explosion Risks
Propane and natural gas CO₂ generators can also be a fire or explosion hazard. To minimize such risks, generators should be kept at a safe distance from flammable items such as plants or chemicals. A sufficient gap is necessary to avoid overheating, and hence a risk of ignition.
Regular service and maintenance is also necessary. Growers should inspect for gas leaks, clean burners and make sure all parts are functioning properly. Keeping a maintenance schedule prevents accidents and guarantees safe operation of the generator.
Maintenance and Troubleshooting
With care and troubleshooting, CO2 generators will work well without problems. Nothing runs well (or safely) when it’s neglected.
Routine Maintenance Tasks
- Clean the burners regularly to avoid the accumulation of dust or other material that may block gas flow.
- Check the ignition electrodes for proper sparking for smooth functioning.
- Examine any tubing on the system for leaks or wear that may interfere with CO₂ delivery.
- Adhere to seasonal shut down and start up procedures and make sure to shut off generator, clean it and check all components before putting it back into use.
- Promoting ongoing maintenance to keep everything running smoothly and prevent surprises.
Common Issues and Fixes
- Uneven CO₂ distribution: A blocked or obstructed burner or insufficient airflow may be responsible. Check for blockage and fan position.
- Faulty controllers or sensors: If levels of CO₂ are out of range, check and recalibrate the controllers or replace any malfunctioning sensors.
- Flame-outs: Propane CO2 generator reviews or natural gas burners reviews indicate that it may fail to work if it is too dirty or if the fuel is running low. Clean the burner and make sure there is sufficient fuel.
- Call a professional: If easy fixes don’t do the trick, such as cleaning or adjusting it, user need to call in a professional to come take a look and repair the generator.
FAQs
What is the best CO₂ level for plant growth?
Optimal CO₂ plant growth level is between 800 and 1,500 ppm. This spectrum is best for faster growing and blooming plants.
How to increase CO2 for plants?
People are able to raise CO₂ in their grow room by utilizing a CO₂ generator, CO₂ tanks or even D.I.Y with stuff like Yeast and sugar for smaller grows.
Do greenhouse growers use CO₂ generators?
Yes, many greenhouse growers use CO₂ generators to enhance plant growth, particularly in large-scale operations where maintaining ideal CO₂ levels matters.
The Bottom Line
CO₂ generators are invaluable tools for those growing in greenhouse or indoor grow room environments. Even healthy plants, thriving in good light and water, may grow slowly and produce smaller harvests in the absence of sufficient CO₂. A CO2 generator for grow tent can solve this problem by adding more carbon dioxide to the air so that plants can grow faster, stronger and have better flowers and fruits. Check out Growcycle for reliable CO₂ related products, such as generators and accessories, which will help growers maintain the ideal health of their plants and achieve the most optimal results.
Disclaimer: This material is for informational purposes only and should not be relied on for legal, medical, financial, or any other form of professional advice.
About the Author
Victor Miller 
Environmental Journalist Focused on Sustainable Agriculture
Victor Miller is an environmental journalist at Growcycle, specializing in sustainable agriculture. With a passion for storytelling, he highlights the latest trends, innovations, and practices that promote ecological balance and responsible farming.
