Selecting the right sensor depends on the application. If the monitored environment experiences periodic exposure to background CO₂ levels, the optimal solution will be a single channel NDIR sensor utilizing ABC Logic™. This sensor will provide in-situ automated re-calibration for the life of the sensor, improving performance and reducing cost of ownership. If the monitored environment is continually occupied or not expected to see diurnal CO₂ concentration cycles (such as hospitals, detention facilities, and indoor agricultural structures), a dual channel NDIR is necessary. Without periodic exposure to background CO₂ levels, firmware-based statistical algorithms cannot be reliably deployed for drift compensation. While the hardware-based reference inherent in the dual channel NDIR sensors can provide excellent drift compensation, recalibration will eventually be required for these NDIR sensors in order to retain factory performance specifications.