FINDING THE SOURCE WITH INFRARED THERMOMETERS
Optical systems of infrared thermometers gather energy from a circular spot which increases with distance. Make sure that your target is larger than the spot size you are measuring. The smaller the target, the closer you should be to it. The further away the more inaccurate the reading.
LOCATING THE ANOMALY
If a temperature anomaly is found by an investigator, since the field of measurement is of increasing size, a second investigator can be used to more accurately locate the temperature variance. Please remember you are not measuring air temperature you are measuring the heat/coolness of the surface you are near. Again, infrared thermometers are NOT measurng air temperature.