What Type of CO2 Sensor Does Airmonitor Plus Use?

Airmonitor Plus uses a high-precision NDIR (Non-Dispersive Infrared) CO₂ sensor to directly measure carbon dioxide levels.

NDIR is widely regarded as the industry standard for accurate indoor CO₂ monitoring and is commonly used in commercial air quality monitors, schools, offices and building management systems.

Does the Airmonitor Plus Measure Real CO₂?

Yes.

The Airmonitor Plus measures actual carbon dioxide (CO₂) using a dedicated NDIR sensor.

Some lower-cost air quality monitors estimate equivalent CO₂ (eCO₂) using VOC (Volatile Organic Compound) measurements rather than measuring carbon dioxide directly. While eCO₂ can provide a general indication of indoor air quality, it is only an estimate and may not accurately represent the true CO₂ concentration.

By using a dedicated NDIR sensor, the Airmonitor Plus provides direct CO₂ measurements for greater accuracy and reliability.

Why Is NDIR Better?

An NDIR sensor measures carbon dioxide by detecting how CO₂ molecules absorb infrared light.

This technology offers several advantages:

Direct measurement of carbon dioxide.

• High accuracy and long-term stability.
• Fast response times.
• Excellent resistance to interference from other gases.
• Reliable monitoring for ventilation and indoor air quality.

These benefits make NDIR the preferred technology for accurately monitoring indoor CO₂ levels.

Why Monitor CO₂?

Carbon dioxide is one of the best indicators of indoor ventilation.

As people breathe, CO₂ levels naturally increase in enclosed spaces. Elevated CO₂ levels can indicate that fresh air isn't entering the room quickly enough.

Monitoring CO₂ can help you decide when to:

• Open windows.
• Increase mechanical ventilation.
• Adjust your HVAC system.
• Improve overall indoor air quality.

CO₂ Measurement Specifications

The Airmonitor Plus measures carbon dioxide within the following range:

• Measurement Range: 400–5,000 ppm
• Accuracy: ±50 ppm + 5% of reading (typical)

This range is ideal for monitoring homes, offices, classrooms and other indoor environments.

Does the Sensor Need Calibrating?

Yes.

To ensure the highest level of accuracy, we recommend calibrating the CO₂ sensor before first use and whenever the monitor has been transported over a long distance or if the readings appear inaccurate.

Calibration is quick and only takes a few minutes. Please refer to our Calibrating the CO₂ Sensor guide for step-by-step instructions.

Frequently Asked Questions

What does NDIR stand for?

NDIR stands for Non-Dispersive Infrared. It is a proven sensing technology that directly measures carbon dioxide using infrared light.

Is an NDIR sensor more accurate than an eCO₂ sensor?

Yes. An NDIR sensor measures actual carbon dioxide, whereas an eCO₂ sensor estimates CO₂ levels based on VOC readings. Direct measurement provides greater accuracy and is the preferred method for monitoring indoor air quality.

Why do I need to calibrate the sensor?

Calibration establishes an accurate fresh-air baseline, helping to ensure the most reliable CO₂ readings over time. We recommend calibrating the sensor before first use and after transporting the monitor.

Can the NDIR sensor wear out?

NDIR sensors are designed for long-term stability and reliability. With normal indoor use and occasional calibration, they can provide accurate CO₂ monitoring for many years.

What is a good indoor CO₂ level?

Outdoor air typically measures around 400–450 ppm. Well-ventilated indoor spaces are usually below 800 ppm, while higher readings may indicate that additional ventilation would be beneficial.