What Are Infrared Thermometers Used For?

Infrared thermometer measuring a circuit board

Infrared thermometers are useful to measure temperature in a wide variety of applications at home and the workplace. In this article, we’ll talk about the more common infrared thermometer uses in more detail.

In industrial workplaces, infrared thermometers are prevalent at job sites where machinery and hazardous or inaccessible objects need to be monitored.

In foodservice applications, restaurants use non contact infrared thermometers to take quick temperature checks of food in a holding unit or buffet line.

Medical infrared thermometers are used for the temperature screening of people at airports, schools, and businesses to help contain the spread of viruses.

There are many advantages of using an infrared thermometer, but the most important are the following:

  • Infrared thermometers can take readings quickly and accurately, allowing for spot checks of several surfaces in seconds.
  • They can take temperatures from considerable distances to help you measure hard to reach places and protect you from extreme heat and cold.
  • They have a wide temperature measurement range.

But there are some key disadvantages too that you’ll want to keep in mind, including the fact that they can only measure surface temperature, not internal temperatures, and visual obstructions like fog and smoke can hinder readings.

If you’re interested in purchasing an infrared thermometer, check out our infrared thermometer reviews of some of the most popular models.

Understanding Emissivity and Distance to Spot Ratio

When using an IR thermometer, there are two variables you’ll want to understand before taking temperature readings to get the best results.

Emissivity

Emissivity is a measurement of how efficient a surface is at emitting thermal radiation and can be a decimal number anywhere from 0 (shiny mirror) to 1 (blackbody). A surface with an emissivity of 0 emits no infrared energy, while a surface with an emissivity of 1 is a perfect emitter and will efficiently radiate the temperature of the object. It’s important that your thermometer’s emissivity setting matches the target’s emissivity to obtain the most accurate readings.

Distance to Spot Ratio

Distance to spot (D:S) ratio is another critical factor to consider before measuring any surface. It refers to the size of the area that the thermometer will measure when a given distance away. For example, an infrared temperature gun with a D:S ratio of 12:1 would measure a 1-inch diameter area from 12-inches away. The further you are away from the object you’re measuring the larger the measurement area becomes.

An Infrared Thermometer Is Best Used to Measure the Temperature Of:

What do infrared thermometers measure? Here are some of the applications where they’ll be most useful.

Infrared Thermometers For Cooking and Food Safety

Check a grill's temperature with an infrared thermometer

Infrared thermometers are excellent tools in the kitchen, but a probe thermometer is likely a better choice for most applications. Since IR thermometers can only measure the surface temperature of an object, they are not ideal for checking meats’ doneness.

However, elsewhere in cooking and food safety, they are useful tools. For example, you can check if a cooking surface is at the correct temperature with an infrared thermometer. Restaurants, especially buffets, will use an IR thermometer to ensure that food is maintained at a proper temperature so it is safe to eat and to prevent cross-contamination that could occur with a probe. You can also use them in walk-in freezers and refrigerators to ensure food is being stored at the correct temperature.

Can You Check Grill Temperatures With an Infrared Thermometer?

Yes. You can use an infrared thermometer to measure the temperature of a grill. Just remember that the device may factor in the temperature of the surface that is visible through the grate. For more accurate temperature readings when measuring a barbecue grill, use a solid cooking surface like a cast iron plate or skillet. Place a skillet on the grill and let it pre-heat for about 5-10 minutes. Then spray it with some cooking oil to ensure proper emissivity before taking a temperature measurement for the best results.

Can You Use an Infrared Thermometer to Measure the Temperature of an Oven?

No. The infrared thermometer will take the temperature of the oven’s walls rather than the interior of the oven itself. A better solution for measuring oven temperature is using an air probe attached to one of the grates if your oven doesn’t already have a thermostat built-in. However, you could use an IR thermometer to measure the surface temperature of a cooking tray or pizza stone.

Can You Check If Food Is Properly Cooked With an Infrared Thermometer?

No. You’ll want a thermometer with an insertable probe to take an accurate reading of the internal temperature of food to gauge the doneness. Infrared thermometers will only measure the surface temperature of the food, which can vary dramatically from the internal temperature.

Infrared Thermometers For Medical Use

Medical forehead thermometer

Infrared thermometers are useful in medical applications for checking body temperature. However, your standard general purpose and industrial thermometers will not be effective for this application. Instead, you’ll want to purchase a medical-grade infrared thermometer as they are calibrated to take human body temperatures. These forehead IR thermometers are programmed to convert forehead temperatures to oral temperature equivalents.

They are designed to safely and quickly take the temperature of children and adults using non-contact infrared technology, which reduces cross-contamination risk and prevents virus and disease transmission. As they can take temperature readings without contact and within one second, they are ideal for use with patients in hospitals and temperature screening purposes at airports, restaurants, offices, schools, etc.

Infrared Thermometers in the Automotive Industry

IR thermometer diagnosing vehicle

In the automotive industry, mechanics and automotive enthusiasts use infrared thermometers to diagnose parts and troubleshoot overheating issues, they’re also used to perform routine spot checks to prevent breakdowns. An infrared thermometer is a valuable diagnostic tool in any garage as it can easily take the temperature of moving and hard to reach components.

They’re useful for checking a wide variety of vehicle systems including, brakes, tires, radiators, HVAC systems, engine timing, belts and pulleys, cooling systems, catalytic converters, and intake air regulation.

Infrared Thermometers in the HVAC Industry

HVAC technician checking the temperature of an air supply register

HVAC technicians use infrared thermometers to diagnose issues with heating and cooling systems. A technician will use a thermometer to measure the temperature of various parts of the system to ensure proper operation. However, most technicians will use air probes instead because they are primarily interested in the output air temperature. As the heated air is transparent, an IR thermometer will instead measure the surface temperature of a nozzle or a housing component, which will be colder than the heated air.

However, there are situations where an IR thermometer can come in handy for an HVAC technician. They can be particularly useful in large offices and factories where instant point and shoot temperatures need to be taken to locate and troubleshoot problems quickly. They can be used to check supply and return registers, identify leaky ducts, isolate faulty insulation, check compressor temperatures, and diagnose any other heat-related problems with an HVAC system.

Infrared Thermometers for Manufacturing

Checking temperature of motor

Manufacturing applications are well suited for IR thermometers, as surface temperatures are often crucial in the production process to ensure the integrity of the products and to help maintain the machinery.

They’re used in quality assurance checks on assembly lines and routine equipment inspections to avoid costly equipment failures.

A non contact infrared thermometer can be useful in detecting heat emitted from loose connectors, checking power supply connections, fuses, and circuit boards in electrical maintenance. Mechanics might use an IR thermometer to check the temperatures of moving parts and housings in motors and gearboxes, as sudden changes in temperature might be early signs of mechanical failure. On an assembly line where the temperature might be critical—such as for candy or plastics—spot temperatures can be taken of the different products as they roll off the line.

Infrared Thermometers for Home Use

Repairing remote control car

In the home, there are many different potential uses for an infrared thermometer. They might help you spot air leaks and poorly insulated portions of the house by detecting differences in the temperature of your home’s walls. If there are significant differences from wall to wall, those cooler walls might need more insulation.

You might also find it useful for your home auto repairs, any other DIY work around the house, and just about everyone will find one to be very handy for cooking preparation. They’re also helpful in a variety of hobbies, whether it be crafting beer, making candles and soaps, electronics repair, remote control toys, etc.

IR Thermometer Frequently Asked Questions

Below we’ve listed several commonly asked questions about IR thermometers that we often hear from our readers.

Q: Can You Measure Water Temperature With an Infrared Thermometer?

A: Yes. If you plan to use your infrared thermometer to measure water or any other liquid, like soup or sauces, vigorously stir it for several seconds to ensure that the liquid on the surface is as close to the temperature below the surface. Keep in mind that boiling water will cause steam that could potentially throw off your readings.

Q: Can Infrared Thermometers Measure Air Temperature?

A: No. As infrared thermometers only measure surface temperature, and the air is transparent. In this case, you’ll want to use an air probe thermometer instead.

Q: Can Infrared Thermometers Work Through Glass or Clear Plastic?

A: No. You cannot take measurements of objects through glass, plastic, or other transparent surfaces. You’ll be taking the temperature of the glass or plastic rather than any object behind it. For infrared thermometers to work correctly, the device must have an unobstructed view of the object itself.

Final Thoughts

Infrared thermometers are fast and accurate thermal instruments that are easy to use in many applications. However, they do have their limitations, and they may not always be the best solution for the job.

With that said, there are some very affordable models on the market, and they will come in handy for numerous everyday applications. We suggest that every homeowner should have one in their toolbox. To learn more about how infrared thermometers work, see our recent blog post.

Published: August 5, 2020

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