Infrared Thermometers: FAQs

Infrared (IR) thermometers offer the same level of accuracy and reliability as that of a rectal or oral thermometer. However, it is also essential to understand that the accuracy depends on how and where you use these thermometers. Make sure to refer to the manufacturer's guidelines and instructions for proper use.

Clinical infrared thermometers are completely safe to use on everyone - babies, children, and adults as long as you don't point the laser beam into their eyes. These non-contact devices also allow measuring the temperature of humans from a safe distance.

The temperature measurement range of infrared thermometers varies according to its type. Clinical IR thermometers for body surface temperature typically have higher accuracy (± 0.1°C) and can measure temperature in the range of 32–42°C. Industrial IR thermometers, on the contrary, have an extensive temperature range, usually between -50°C and 1000°C.

There are several ways to calibrate your infrared thermometer.

One of the popular techniques is to use a black body calibrator, which consists of a cavity with a small opening. A perfect black body has an emissivity of 1. Emissivity is the effectiveness of an object's surface to emit infrared energy as thermal radiation. Set the emissivity value in your IR thermometer temperature gun to 1 or the value provided by the black body calibrator. Now, connect a trusted thermocouple on the black body cavity surface. Record the temperature measured by the thermocouple and set this temperature value in your IR thermometer. Your IR thermometer is now calibrated.

Another easy method to calibrate your infrared thermometer is by comparing its temperature measurement with the one obtained from a CE approved contact thermometer. Calculate the difference between the temperature values and adjust this difference in your IR thermometer's calibration settings. Measure the temperature again with both the devices and compare the values. If the values are similar, your device is calibrated and ready for use.

Follow the steps below to measure the surface temperature of a subject using a non-contact infrared thermometer.

• Turn ON the IR thermometer and press & hold the trigger for the laser beam to appear.
• Point the laser beam in the direction of the subject you want to collect the temperature readings for.
• Make sure that the laser beam is stable and is pointing at the central location.
• If possible, stay as close to the subject as possible for accurate readings.
• Press & hold the trigger while the thermometer records the subject's temperature.
• The recorded temperature will get displayed on the thermometer's digital display.
• Note down the readings and turn OFF the device after use.

Determining the accuracy of an infrared thermometer requires a known surface temperature or a trusted surface temperature measuring device, such as a thermocouple for comparison. Measure the temperature of the subject in consideration with the trusted thermocouple and compare the readings with the one obtained from the infrared thermometer. Calibrate the thermometer depending on the temperature difference using the device's built-in settings.

Alternatively, perform an ice water test by filling a glass with ice and adding enough water to fill the gaps formed between ice cubes. Stir a few times for a uniform surface. Now, point your infrared thermometer directly on top of the ice-water surface at a distance, not more than 5 cm. Make sure that the thermometer lens is at a 90° angle, and the laser is pointing at the surface's center. Record the temperature with this setting. If your IR thermometer reads approximately 32°F (0°C), your device is within the specified accuracy.

No. infrared thermometers cannot measure the temperature accurately if there is glass, liquids, or any transparent surface between the subject and thermometer. The temperature values displayed in such conditions are of a transparent surface and not the subject.