The self-calibration function in Senseair sensors allows you to install the sensor and not worry about its accuracy for 15 years!
All Senseair sensors require no additional maintenance thanks to the built-in ABC (Automatic Baseline Correction) algorithm, which automatically adjusts the readings. This ensures the device's longevity and eliminates the need for regular calibration under standard operating conditions.
How the ABC Algorithm Works
The ABC algorithm continuously analyzes the sensor's minimum readings over a set period and gradually corrects long-term deviations, based on the CO₂ value in fresh air — 400 ppm (0.04% vol.). In typical indoor environments, the carbon dioxide level periodically drops to the outdoor air level. The sensor records values over 8 days, compares the minimum reading to 400 ppm, and adjusts the zero point if necessary.
If the sensor detects hydrocarbons, their concentration is usually close to 0 ppm.
Causes of Reading Drift
Sensor accuracy can be affected by rough handling, transportation, or natural aging of components. However, the ABC function gradually restores readings to correct values over time.
What to Do If the Room Is Occupied All Day?
In rooms where the CO₂ level never drops to the baseline (e.g., greenhouses or sealed spaces), the ABC algorithm cannot operate correctly. In such cases, it is recommended to disable the function and perform manual calibration every 2–3 years.
If the Baseline Level Differs from 400 ppm
The ABC algorithm assumes the minimum CO₂ level corresponds to 400 ppm, but in reality, it may be higher or lower. However, for ventilation control, the difference between indoor and outdoor CO₂ concentrations is what matters. For example, even if the minimum level is 450 ppm, the ventilation system will be effective because it considers the difference between the baseline and current readings. This is similar to constantly comparing sensor data with outdoor conditions.
Calibration Maintenance Period
The sensor maintains calibration accuracy as long as it periodically records the baseline CO₂ level. The device components are designed to operate for 15 years, and calibration remains stable throughout this period.
An Important Criterion When Choosing Sensors
Some sensors may be cheaper, but when comparing, it is important to consider not only the initial cost but also durability and maintenance expenses over the entire service life.
To choose suitable CO2 concentration sensors and transducers using the ABC algorithm, contact our specialists for assistance.
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