The warm-up time / adjustment time is the time that a pyrometer, infrared temperature sensor or infrared thermometer needs to adjust to the ambient temperature (see ambient temperature compensation).

Once the sensor has been installed, the temperature compensation must adapt to the ambient temperature conditions and a thermal equilibrium must be reached at all parts of the sensor. This adjustment time is necessary to ensure that the measuring system provides optimal temperature detection.

The greater the difference between the device temperature and the ambient temperature, the longer is the adjustment time.

Example: a sensor is taken from the device storage, which has a room temperature of 15°C, and placed in a machine where the ambient temperature is 50°C.