How to Reset an Infrared Thermometer

An accurate reading is everything that is needed when using a thermometer. Infrared thermometers use radiated energy emitted by a body or object to detect and display its actual temperature. Whether you use the infrared thermometer to measure body temperature, for cooking or any other purpose, it needs to provide accurate measures.

Infrared thermometers might, over time, get less calibration, thereby making them give inaccurate readings. Therefore, you need to reset them more often to enable them to serve you best for extended periods. In this article, you will learn how to use the IR thermometer, how you can reset it and ways to get accurate measurements with the IR thermometer.

How the Infrared Thermometer works

The human body, as well as all other objects around, can emit, gather or absorb infrared energy. The infrared thermometer uses best thermal radiations emitted by an object to detect its temperature. The lens of the thermometer gains infrared radiations from an object and gathers them to the thermopile, the Infrared thermometer detector.

The absorbed infrared radiations are converted into heat in the thermopile and then into electricity. The electricity is what is indicated on the screen of the infrared thermometer in the form of temperature. Therefore, the amount of radiations emitted by an object determines the temperature reading. If a body emits more infrared radiations, it will result in more electricity conversion and thus a higher temperature reading of the body or object.

How to Correctly Use an Infrared Thermometer

correctly use an infrared thermometer

Sufficient information about the IR thermometer is needed for you to use it correctly. The IR thermometer measures the temperature of a bigger area. The distance between the thermometer and the measuring body plays a role in the overall thermometer reading.

Some environmental elements and factors play a role in the final thermometer temperature reading. Dust and steam can affect the accuracy of results; therefore, you need to be extra careful about your surrounding before you embark on the exercise. The lens should always remain clean with no scratches so that you get accurate readings. A single measure isn’t enough, measure a body or object twice or thrice for accurate readings.

Besides this, there are several expert tips in place to help you to get accurate temperature measurements. Below are five additional tips to make use of the Infrared thermometer;

  • If you need to measure the temperature of a certain liquid or food, ensure to stir it evenly before taking measurements
  • Since sudden ambient temperature changes can affect the overall temperature reading, you need to leave the thermometer in the area you plan to measure for about 20 minutes before embarking on the actual measuring exercise.
  • Ensure there is no barrier between the object you plan to measure and the thermometer. Nearby objects or covers will affect the reading since they will also emit radiations.

Note: Avoid looking directly into the beam when taking readings since radiations emitted can cause permanent eye damage.

Resetting an Infrared Thermometer

After you have information on how to use the Infrared thermometer correctly, it’s now time to focus on how you’ll get accurate results from your Infrared thermometer. You need to always reset your thermometer for accurate readings.


  • The transfer standards
  • Partition
  • Thermal radiation source
  • A distance measuring device
  • Ambient temperature thermometer
  • Mounting device

These are the necessary equipment you need to reset your infrared thermometer. Let’s have a look at the role the equipment play in the resetting process.

The transfer standards

You need either a highly calibrated infrared thermometer or a control probe in that case for accuracy testing. Get a tool verified from a professional or an independent national lab for this purpose.

A partition

You get accurate thermometer readings if you keenly focus on the particular object you are taking its temperature measurements. The partition will limit the amount of optics around the testing area to ensure you give you an accurate measurement.

A thermal radiation source

They are commonly referred to as black bodies. The black bodies are defined by zero reflected ambient radiation. Since you will calculate the distance between the radiation and your tool, you must note the size of the radiation source.

In case you choose to use more than one black body, ensure they don’t face each other since they will transmit radiated energy back and forth, thereby affecting your final reading.

Mounting device

Mounting devices are important for proper alignment so that you get a more stable measurement. It will also be easy when measuring distance. You can consider using either a tripod or any other fixture as your mounting device.

Distance measuring device

Distance between the radiation and your tool is important for final calculations. You can either use a measuring rod or a tape measure to measure the distance.

The ambient temperature thermometer

While doing the exercise, you need to monitor the environmental conditions at the testing site. You need to learn about the temperature changes, humidity level and any other important element that can bring an effect to the general thermometer reading.

For this reason, get an accurate thermometer to monitor all environmental changes as they happen throughout the process. An accurate thermometer also helps to monitor changes in other ambient temperatures or sudden temperatures from an AC.

There are various methods you can reset an Infrared thermometer, some of the most applied options include;

  • Usage of an Ice bath
  • Using an infrared comparator cup
  • The laboratory-based calibration method

Usage of the infrared comparator cup is the simplest and inexpensive method to reset an Infrared thermometer. It helps to reset thermometers for temperature readings taking place more than once.

Ice bath resetting method, on the other hand, resonates around factoring the boiling point of a liquid. Environmental elements such as air pressure and point of elevations greatly affect temperature measurements. You need to prepare an Ice bath that provides you with a maximum of zero degrees so that you attain accurate reading.

Lastly, the laboratory-based method is an advance thermometer resetting method. You can use any of the above methods to get your Infrared thermometer back to its working conditions. However, usage of a well-wended ice bath and the boiling water are the most convenient methods to reset an IR thermometer. Below is a step by step guide you can follow to get through the resetting process successfully;

The Ice point method

Step 1

First, crush some ice and fill them into a large glass to the top. Follow by adding cold water to a level of an inch. Stir the components in the glass gently and let the mixture sit for about two minutes.

Step 2

Ensure there is no ice floating on water. You can do this by tamping the ice down to get a layer of open water on the top of the glass.

Step 3

Before you embark on the real resetting exercise, set your Infrared thermometer to an emissivity of between 0.95 and 0.97.

Step 4

Now it’s the time to reset your infrared thermometer. Hold it gently with the lens pointing perpendicular to the surface of your ice bath. Ensure you are pointing closer to the ice bath since your overall measurements will include that of the container and objects nearer if you did the exercise far off from the surface of the ice bath.

Step 5

Lastly, ensure the field of view is well catered inside the container. Ensure the lens focuses well inside the sides of the glass. Switches on the thermometer and take readings.

The thermometer should read the set specified thermometer accuracy of 32.0°F (0.0°C). However, you will get the correct reading if you did the test correctly.

The boiling point method

This is another commonly used method to reset an infrared thermometer we have around. With just a few steps, you will have your thermometer back to its original state to give you accurate readings. Let’s have a look at the step by step guide to get through with the boiling point method;

Step 1

Start by boiling distilled water to a rolling boil in a deep pan. Don’t stop; keep boiling the water until the exercise is complete.

Step 2

Place the thermometer probe slowly at the centre of the boiling water. Ensure it doesn’t touch the sides of the pan or the bottom surface. Throughout the process, ensure to protect the hands from steam.

Step 3

Give it a few minutes for the indicator to stabilize. Take the reading of your thermometer; it should read 212°F (100°C)

In case you register a different reading, push the reset button while the thermometer probe is in the boiling water and make adjustments to 212°F (100°C).


The infrared thermometer is an ideal instrument to provide you with an immediate and accurate measure of the temperature of a body or object. In this article, you’ve learned all information about the infrared thermometers and what is required for it to give you accurate measurements. Resetting your thermometer is important if you deem to get accurate results all through. The activity should be carried regularly before embarking on measuring the temperature of a certain object or body.

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