A non-dispersive infrared (NDIR) sensor has a detector that measures how much infrared light of a specific wavelength is absorbed by the surrounding air. This measurement is then used to calculate the concentration of a specific gas.

Compared to electrochemical sensors, the lifespan of the NDIR sensor is very long. This is mostly because these sensors have no sensor burn-out, nor any sensor deterioration upon exposure to gases. Furthermore, the interference from other gases in the measurements is minimal to zero for NDIR sensors, depending on which gas is to be measured.

In regard to semiconductor sensors, they perform best in higher concentrations (2,000 – 10,000 ppm) and are cross-sensitive to humidity and temperature fluctuations. The semiconductor sensors can deteriorate as non-target gases may be absorbed by the oxide surface.

For the gases where NDIR-sensors can measure the concentration, the sensors have none of these problems and work well for all concentrations of the target gas. Altogether, the major advantages of NDIR sensors are low life-cycle cost and a precise and stable long-term operation.

All sensors drift over time, which means that recalibration is needed for long-term accuracy.

With Senseair’s automatic baseline correction, the drift in our NDIR sensors is automatically corrected in normal indoor applications, which eliminates the need to manually recalibrate the sensors. This results in a maintenance-free sensor that has a life expectancy with maintained accuracy of at least 15 years.