Autopilot Liquid Propane CO2 Generators – 8 Burner 18,108 BTU 21.1 CuFt/Hr

The Autopilot 8-Burner Liquid Propane CO2 Generator produces 21.1 cubic feet of CO2 per hour at 18,108 BTU, covering grow spaces up to 28’ x 28’. Built around precision brass burners, a solid-state electronic ignition module, and a powder-coated steel enclosure, it delivers consistent carbon dioxide enrichment without a standing pilot light and operates for only pennies a day in propane cost.

Autopilot 8-Burner LP CO2 Generator Specifications

All specifications below are drawn from manufacturer documentation for model APGP0800.

Specification	Value
Model / SKU	APGP0800
Fuel Type	Liquid propane (LP)
Number of Burners	8
Heat Output	18,108 BTU
CO2 Output Rate	21.1 cu ft/hr
Maximum Coverage Area	28’ x 28’ (784 sq ft) and smaller
Enclosure Material	Powder-coated steel
Burner Material	Precision manufactured brass
Ignition Type	Solid-state electronic (no pilot light)
Tip-Over Shutoff	Yes — engages at 30° ± 5°; resets at ≤10°
Error Indication	LED shutdown warning indicator lights
Unit Weight	27.6 lb
Mounting Method	Suspended / hanging (unrestricted bottom airflow required)
High-Altitude Version	Available separately

Why Choose the Autopilot 8-Burner LP CO2 Generator

CO2 enrichment is one of the highest-return investments a grower can make in a sealed or semi-sealed environment. Plants at ambient CO2 levels (around 400 ppm) are supply-limited; raising CO2 to 1,000–1,500 ppm removes that limitation and allows photosynthesis to run closer to its genetic ceiling. The Autopilot 8-Burner LP generator is designed for growers who need meaningful output — 21.1 cubic feet per hour — in spaces up to 28’ x 28’ without the recurring cost and handling logistics of compressed CO2 tanks.

The following features distinguish this unit from passive CO2 sources (bags, tabs) and from cheaper burner designs:

• Solid-state electronic ignition with no standing pilot light. The ignition module creates a spark on demand each time the unit fires. There is no continuously burning pilot flame wasting gas between cycles, which reduces propane consumption during off-periods and eliminates a common failure point found in older pilot-light designs.
• Precision brass burners. Brass resists oxidation and corrosion better than plated steel alternatives, maintaining a consistent gas-to-air mixture over the life of the unit. All eight burners are factory-matched to provide even CO2 distribution across the coverage area.
• Powder-coated steel enclosure. The enclosure resists moisture, rust, and discoloration in the high-humidity conditions typical of a closed grow room. Autopilot describes this as providing years of trouble-free operation, and the finish choice reflects a deliberate decision to use a material that holds up to condensation cycles.
• Tip-over safety shutoff. If the unit is knocked, bumped, or falls while suspended, a mechanical switch cuts the gas supply. The switch engages at 30° (±5°) from vertical and resets automatically when the unit is returned to within 10° of vertical. This is a meaningful safety feature in an active grow environment where ropes can slip or equipment can be bumped.
• LED shutdown warning. When the unit detects a fault and shuts down, LED indicator lights alert the grower. Without this, a mid-cycle shutdown in an automated room could go unnoticed for hours, causing CO2 levels to drop without warning.
• Low operating cost. Propane combustion is a cost-effective CO2 source for large-volume spaces. At 18,108 BTU per hour across eight burners, the generator can maintain target CO2 concentrations in a 784 sq ft room during the light cycle without running continuously, keeping per-cycle propane costs low.

Best Uses for the Autopilot 8-Burner LP CO2 Generator

This generator is sized for medium-to-large commercial and semi-commercial grow operations. The following scenarios describe where it performs best:

• Sealed grow rooms up to 28’ x 28’ (approximately 784 sq ft). In a sealed room with adequate air circulation, the 21.1 cu ft/hr output rate provides enough CO2 volume to maintain enriched concentrations through a typical light cycle. Growers running single-room production in this size range will find the 8-burner unit appropriately sized — neither under-powered (forcing continuous run) nor oversized (making PPM control difficult).
• Rooms where propane supply is more practical than CO2 cylinders. Compressed CO2 cylinders require frequent delivery or exchange, adding operational overhead and the risk of running empty mid-cycle. Connecting to a bulk propane supply or standard liquid propane tanks keeps the CO2 source on-site and reduces the frequency of intervention. This is especially valuable for growers running automated environmental control.
• Automated environment setups paired with a CO2 controller. Autopilot notes that these generators are designed to work with Autopilot environmental controllers. Growers using a CO2 controller — such as the Autopilot PX2 controller — can wire the generator to fire only when CO2 drops below the target setpoint, making enrichment fully automated and avoiding overproduction.
• Facilities at standard elevation. This unit is the standard (low-altitude) version. It is appropriate for grow sites near sea level through moderate elevation. Autopilot offers high-altitude versions for facilities where thinner air affects combustion ratios; use those variants for sites at significant elevation gain.
• Growers switching from bags or passive CO2 sources. Passive CO2 bags are suitable for small spaces and hobbyist grows, but they cannot reliably supply the volume needed for a 700+ sq ft room. The 8-burner LP generator provides precise, controllable output that can be cycled on and off via a controller, which passive sources cannot match.

Compatibility

The Autopilot 8-Burner LP CO2 Generator runs on standard liquid propane (LP). It is not interchangeable with the natural gas version — Autopilot makes both, and the gas orifice sizing differs between fuel types. Confirm your fuel supply before ordering.

The unit must be suspended from above — mounting on a shelf or setting it on a surface is not acceptable. The design requires unrestricted airflow through the bottom of the enclosure to support complete combustion. Suspending the unit also keeps it above plant canopy and allows exhaled CO2-rich air to settle down through the room, which is consistent with CO2’s density (heavier than air).

For automated CO2 management, the generator is compatible with any CO2 controller that uses a standard switched outlet or dry-contact relay to cycle the gas supply. Autopilot’s own environmental controllers are tested and recommended for this pairing. A CO2 controller such as the Autopilot PX2 handles the on/off cycling based on a sensor reading, eliminating the need for manual monitoring.

If your room uses active air exchange — such as an inline fan drawing in fresh air or exhausting stale air — note that air exchange will dilute CO2 concentration. CO2 enrichment is most effective in sealed or near-sealed rooms where air exchange is minimal during the CO2 injection period. Running an air filtration pre-filter on your intake can help maintain air quality without requiring excessive exchange volume. High-altitude installations require the separate high-altitude version of this generator.

Usage Guidelines

CO2 enrichment operates during the light cycle only. Plants consume CO2 through photosynthesis, which requires light; enriching CO2 during dark periods provides no growth benefit and wastes fuel. Most automated CO2 controllers include a photocell or accept a signal from the lighting timer to enforce this automatically.

Target CO2 levels: Typical enrichment targets for indoor cultivation range from 1,000 to 1,500 ppm. Levels above 1,500 ppm are generally not beneficial and can be wasteful; levels below 800 ppm provide diminishing enrichment benefit over ambient air. Keep a calibrated CO2 sensor in the room at canopy height to monitor actual ppm and avoid over- or under-enriching.

Coverage calculation: Autopilot rates this 8-burner unit for spaces of 28’ x 28’ and smaller. In practice, actual cycle duration depends on room volume (height matters, not just floor area), baseline CO2 level, and target setpoint. A room with 10’ ceilings contains more air volume than one with 8’ ceilings, meaning the generator runs slightly longer per cycle to reach the setpoint. Taller rooms may require slightly longer injection periods.

Heat load: At 18,108 BTU per hour, this generator adds heat to the grow space during each cycle. In warm climates or during summer months, factor this heat load into your HVAC and dehumidification sizing. The generator fires in short cycles rather than continuously, so the average heat addition is a fraction of the peak BTU figure, but it is a real contributor to room temperature that should be accounted for in climate control planning.

Ventilation during off-cycles: If the room requires periodic air exchange for odor control or temperature management, coordinate air exchange with CO2 off-periods (typically timed to the light-off period) to avoid flushing enriched CO2 out of the room unnecessarily.

How to Install the Autopilot CO2 Generator

1. Plan the mounting location. Select a hanging point near the center of the room and above the canopy. The unit requires unrestricted airflow through the bottom of the enclosure, so do not mount it flush against a wall or ceiling surface. Allow at least 12 inches of clearance below any fixed surface above the unit.
2. Install hanging hardware. Use appropriately rated ratchet hangers, chain, or rope rated for the unit weight (27.6 lb) plus a safety margin. Route the hangers through the enclosure’s designated mounting points. Confirm the unit hangs level — if it tilts beyond 10° from vertical at rest, the tip-over switch may prevent ignition.
3. Connect the propane supply. Use a regulator and hose rated for LP gas at the appropriate pressure for this generator. Consult Autopilot’s installation documentation for the correct inlet pressure specification. Use appropriate thread sealant on all gas fittings and inspect all connections for leaks with soapy water or an LP-rated leak detector before powering the unit on.
4. Connect to a CO2 controller or timer. Plug the generator’s power cord into a switched outlet controlled by a CO2 controller or a timer set to the light cycle. Do not leave the generator running continuously on manual power without a controller — CO2 levels will exceed safe targets.
5. Test ignition. With the gas supply open and the controller or timer sending power to the unit, observe ignition. The solid-state module will spark and the burners will light. Verify all eight burners are burning evenly with a stable blue flame. Uneven or yellow-orange flame indicates an air/gas ratio issue that should be resolved before normal operation.
6. Calibrate and monitor. Place a CO2 sensor at canopy height and monitor readings over the first several light cycles. Adjust controller setpoints as needed to reach your target ppm without sustained overshoot. Log temperature to confirm the heat contribution is within your HVAC capacity.

Sources & Further Reading