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Best Contactless IR Thermometers & Thermal Guns

The 10 Best Infrared Thermometers & Thermal Guns: Reviews & Buying Guide

Shopping for a contactless infrared thermometer? 

You’ve come to the right place. 

Infrared thermometers, also called non-contact thermometers or thermal guns, are used to measure the temperature of different surfaces from a distance.

An infrared thermometer collects thermal radiation (black body radiation) emitted by an object.

A lens focuses the radiation on a detector that turns the infrared radiation into an electric signal. A sensor uses the electrical signal to determine the temperature of the target object.

An infrared thermometer is useful in circumstances where a contact temperature probe cannot be used because either it’s dangerous to get too close to the surface or the expected temperature exceeds the recommended maximum for a contact thermometer.

For example, you can use an IR thermometer to measure a very hot surface like an oven, grill, or a car engine.

An IR thermometer is also handy for measuring human temperature without coming into contact with a person.

What's in This Guide?

In this buying guide, we review and compare the best contactless IR thermometers & thermal guns.


Types of Infrared Thermometers

Non-contact thermometers

Spot infrared thermometers: These are the most common types of IR thermometers. They are used to measure the temperature of an object at a spot. The accuracy of these thermometers is greatly determined by the D:S or distance-to-spot ratio. The higher the D:S ratio, the more accurate the thermometer.

Infrared scanning systems: These are used to scan over a wider area. They are mostly used during manufacturing.

Thermal imaging cameras: Thermal cameras work like infrared thermometers, taking infrared light and using it to determine an object’s temperature.


The main difference is that a thermal camera detects the temperature of multiple spots over a wide area and then creates a thermal image called a thermogram. 


Different colors on the image indicate how hot or cold a particular spot.


Top 10 IR Temperature Guns

  1. 1
    Most accurate: Etekcity Lasergrip 1022 Temperature Gun
  2. 2
    Best for Infants - Amplim Non-Contact Thermometer
  3. 3
    Best budget thermal gun for prosFluke 59 Max IR Thermometer
  4. 4
    Best for construction site applicationsDEWALT DCT414S1 IR thermometer kit
  5. 5
    Best for instant troubleshooting: FLIR TG165 Spot Thermal Camera
  6. 6
    Best for Cooking & AutomotiveAmprobe IR-730
  7. 7
    Best for Home Repairs & MaintenanceKizen LaserPro LP300
  8. 8
    Best for Baking: Etekcity 1080 Contactless Thermometer 
  9. 9
    Best for Automotive use: SIMOEFFI Touchless Temperature Gun
  10. 10
    Best for Distant TargetsAmprobe IR-750 Infrared Thermometer

Etekcity Lasergrip 1022
  • Etekcity Lasergrip

  • Most Accurate
  • Range:
    -58°F to 1022°F

  • Adjustable emissivity:
    Yes

  • D:S ratio:
    12:1

  • Power:
    9V battery

  • Weight:
    6.1 ounces

  • Warranty:
    2 years

temp reader gun
  • Amplim Non-Contact Thermometer

  • Best for Infants
  • Range:
    -

  • Adjustable emissivity:
    -

  • D:S ratio:
    -

  • Power:
    2 AAA batteries

  • Weight:
    7.2 ounces

  • Warranty:
    2 years

Fluke 59
  • Fluke 59 Max

  • Best Budget Thermal Gun for Pros
  • Range:
    -22°F to 662°F

  • Adjustable emissivity:
    Yes

  • D:S ratio:
    8:1

  • Power:
    1 AA battery

  • Weight:
    7.7 ounces

  • Warranty:
    1 year

DEWALT DCT414S1
  • DEWALT DCT414S1

  • Widest Range
  • Range:
    20°F to 932°F

  • Adjustable emissivity:
    Yes

  • D:S ratio:
    12:1

  • Power:
    Rechargeable 12V Li-ion battery

  • Weight:
    73.2 ounces

  • Warranty:
    3 years

FLIR TG165
  • FLIR TG165

  • Best for instant troubleshooting
  • Range:
    -13℉ to 572℉

  • Adjustable emissivity:
    Yes

  • D:S ratio:
    -

  • Power:
    Rechargeable Li-Ion battery

  • Weight:
    13.9 ounces

  • Warranty:
    2 years

Kizen LaserPro LP300
  • Amprobe IR-730

  • Best for Cooking & Automotive
  • Range:
    -26°F to 2282°F

  • Adjustable emissivity:
    Yes

  • D:S ratio:
    30:1

  • Power:
    9V battery

  • Weight:
    17.6 ounces

  • Warranty:
    1 year

Amprobe IR-730
  • Kizen LaserPro LP300

  • Best Budget IR Thermometer For Consumers
  • Range:
    -58°F to 1112°F

  • Adjustable emissivity:
    Yes

  • D:S ratio:
    12:1

  • Power:
    2 AA batteries

  • Weight:
    8.8 ounces

  • Warranty:
    Lifetime

point and shoot thermometers
  • Etekcity 1080 Contactless Thermometer

  • Best for Home Repairs
  • Range:
    -58℉ to 1022℉

  • Adjustable emissivity:
    Yes

  • D:S ratio:
    12:1

  • Power:
    1 9V battery

  • Weight:
    6.4 ounces

  • Warranty:
    2 years

non contact thermometer reviews
  • SIMOEFFI Touchless Temperature Gun

  • Best for Automotive Use
  • Range:
    -58℉ to 1202℉

  • Adjustable emissivity:
    -

  • D:S ratio:
    12:1

  • Power:
    1 9V battery

  • Weight:
    8.43 ounces

  • Warranty:
    -

Amprobe IR-750
  • Amprobe IR-750

  • Best for Distant Targets
  • Range:
    -58°F to 2822°F

  • Adjustable emissivity:
    Yes

  • D:S ratio:
    50:1

  • Power:
    9V battery

  • Weight:
    12.2 ounces

  • Warranty:
    1 year


Etekcity Lasergrip 1022 Temperature Gun

With a high distance-to-spot ratio of 12:1, the Etekcity Lasergrip provides high-temperature accuracy while keeping you safe from the hot surface.

A built-in laser and the ability to adjust emissivity for different types of surfaces further ensure high accuracy.

Pros

  • High accuracy.
  • Easy and safe to use.
  • Adjustable emissivity.
  • Wide temperature range.
  • Fast temperature readings (less than half a second).
  • Large backlit display.

Cons

  • Doesn't include a carry case.
  • No weather protection - not ideal for outdoor use.

Our Review 

The Etekcity Lasergrip is a great general purpose thermal gun. Use it to diagnose your HVAC, check the temperature of your oven, or check if your car engine is overheating.

The Etekcity IR thermometer has a distance-to-spot ratio of 12:1, meaning you can measure a 1" wide spot accurately from 12" away.

The high D:S ratio improves measurement accuracy and ensures you don't have to get too close to the target object,

An integrated laser helps you pinpoint exactly the spot you are measuring.

If you often measure different surfaces, you can adjust the emissivity settings on the Etekcity thermometer to ensure you retain accuracy across varied surfaces.

Temperature readings are shown on a large LCD screen in big, easy-to-read numbers.

Buttons below the screen allow you to switch between Celsius and Fahrenheit, activate hold (the screen freezes the temperature reading on the screen for 15 seconds to allow you to read it), and adjust emissivity.

The screen is backlit so you can easily see the temperature in low light environments.

The Etekcity runs off a 9V battery that's included with the thermometer. 

You'll get about 12 hours of continuous battery life, which translates into weeks or months of use depending on how often you use the thermometer.

Replacing the battery is easy.

Issues & Limitations

The Etekcity Lasergrip 1022 thermal gun cannot measure the temperature of humans or animals. It's not dangerous to use it on a person, but you'll get inaccurate readings.

In fact, several customers have tried it. They got accurate readings on surfaces like an oven or HVAC, but the thermometer was several degrees off when measuring someone's temperature.

If you need a human thermometer, we have a good recommendation further below.

Another limitation is that the Etekcity Lasergrip 1022 is not ideal for outdoor use as it does not have any weather protection rating. If your work involves being in the sun, snow, or rain, look for another thermal gun.

The Etekcity Lasergrip 1022 also doesn't come with a carry bag, a downside if you plan to travel with it.

Bottom Line 

The Etekcity Lasergrip 1022 is a great choice for anyone looking for an accurate infrared thermometer for inanimate objects. 


It's ideal for general home use and professionals dealing with HVAC systems, cars, appliances, and other machinery.

2. Best for Infants: Amplim Non-Contact Thermometer

accurate infrared thermometer

Pros

  • Sleek and compact design
  • High-quality LCD display
  • Audible alarm for high temperature
  • Stores past 35 readings
  • Fahrenheit and Celsius
  • 2-year warranty

Cons

  • Need to be close to the person to get an accurate measure, may not be suitable for preventing infectious disease (COVID)

Our Review

The Amplim non-contact thermometer uses a high-precision sensor and is ideal for measuring the body temperature of infants. 

This sleek silver-white thermometer has a green LCD that clearly displays temperature readings. 

The screen is color-coded and turns red when a fever temperature is exceeded. There is also an audible alarm for the same.

The unit automatically stores the past 35 readings, so you can keep track of how the treatment is going in either Fahrenheit or Celsius. 

This Amplim non-contact thermometer is known for its reliability and comes with a 2-year warranty. 

Issues & Limitations

One downside of the Amplim non-contact thermometer is that you must be close to the person to obtain the correct temperature.

Keeping the thermometer too far away from the person results in inaccurate readings.  

This means it isn’t really suitable for measuring people who may be contagious with a dangerous disease.

The Amplim thermometer also does not measure an object's maximum and minimum temperatures, so if you need those, you will have to take many readings to sort that out. 

Bottom Line

The Amplim non-contact thermometer is an excellent tool for detecting fever in patients of any age. 

The onboard log of 35 readings also makes keeping records straight a bit easier.


3. Best Budget Thermal Gun for ProsFluke 59 Max IR Thermometer

Fluke 59 Max IR Thermometer

With its hardy construction, high accuracy and easy portability, the Fluke 59 Max is a great choice for professionals and any homeowner and DIYer looking for high quality and long-lasting IR thermometer.

Pros

  • IP40 protection.
  • An integrated laser ensures accuracy.
  • Small enough to fit in a toolbox.
  • Hardy construction – ideal for harsh environments.
  • Adjustable emissivity.

Cons

  • No water or dust protection.
  • No memory.

Our Review 

The Fluke 59 Max is an entry-level professional IR thermometer.

It's not as good as some of the pricier options in the market are, but it's a big upgrade from basic thermal gun designed for home use.

The Fluke 59 Max has a wide temperature measurement range between -22°F and 662°F, making it ideal for measuring a wide range of machines and systems.

With an 8:1 D:S ratio, the Fluke 59 lets you stay a safe distance from the target object.

A built-in laser helps you pinpoint your target while adjustable emissivity ensures accuracy when testing different surfaces.

The Fluke 59 Max displays the temperature on a large backlit screen. 

Using buttons below the screen, you can also view the max temperature is taken, the min temperature, the DIF (the difference between the max and min), and the average.

You can set upper and lower limits, and an alarm will go off if the recorded temperature is outside this limit. This is handy when diagnosing an appliance, system, or machine.

The Fluke 59 Max has undergone a 1M drop test, making it ideal for harsh environments where it is likely to be dropped or banged against objects.

For easy portability and storage, the Fluke 59 Max comes with a carry case.

Issues & Limitations 

While the Fluke 59 Max is hardier than a basic home IR thermometer, be careful not to expose it to the elements.

The IP40 rating means it's protected only from tools and small wires bigger than 1mm. There's no dust or water protection.

Another thing pros should note is that the Fluke 59 Max lacks an internal memory. You cannot store and recall readings.

Bottom Line 

The Fluke 59 Max IR thermometer is a great choice for pros looking for an accurate and hardy thermal gun on a budget.


4. Best for Construction Site ApplicationsDEWALT DCT414S1 IR Thermometer Kit

DEWALT DCT414S1 IR thermometer kit

The DEWALT DCT414S1 lets you adjust emissivity in increments of 0.01. This allows you to make fine adjustments when measuring the temperature of different surfaces.

For pros who deal with a wide range of materials, the DEWALT DCT414S1 IR thermometer is the best choice.

Pros

  • Fine emissivity adjustments.
  • Wide measurement and operating range.
  • Visual/audio alarm.
  • Data storage with calculations for min, max, and average.
  • Backlist display.
  • Comes with a hard carry/storage case.

Cons

  • Pricey.
  • Heavier than most thermal guns.

Our Review 

The DEWALT DCT414S1 IR thermometer is another good choice for pros who want a hardy and accurate thermal gun. It is especially ideal for pros who measure many different surfaces.

To ensure accuracy, the DEWALT DCT414S1 comes with adjustable emissivity ranging from 0.1 to 1.0. More importantly, you can increase or decrease emissivity by as little as 0.01. You can set the exact emissivity for a particular type of surface.

A 12:1 D:S ratio ensures accuracy while keeping your hand a safe distance from the target. The DEWALT DCT414S1 also comes with a built-in laser for pinpoint targeting.

The screen is easy to read. Because it is backlit, you can measure temperatures in any kind of light environment.

The display is color-coded. It'll light up in red when it encounters a hot area and blue for cold areas. An alarm will also sound if there is a sudden change in temperature, indicating a trouble spot.

The DEWALT DCT414S1 stores readings and can display the max, min, and average of previous readings.

One thing pros will appreciate is the wide measurement range of the DEWALT DCT414S1. It can measure temperature as low as -20°F and as high as 932°F. The wide range gives you more versatility in terms of appliances, machines, and systems you can use the thermal gun on.

The operating range (14º F TO 122º F) is also wider than with most IR thermometers.

For power, the DEWALT DCT414S1 runs on a rechargeable 12V lithium-ion battery.

Issues & Limitations 

The DEWALT DCT414S1 is pricey. If you are shopping for a budget IR thermometer, this is not it.

The DEWALT DCT414S1 is also not a good choice if you want a compact and lightweight thermal gun. It weighs 4.5lbs and probably won't fit in your toolbox. Luckily, it comes with its own hard carry case.

Bottom Line 

The DEWALT DCT414S1 is a great choice for pros who want a versatile infrared thermometer that can accurately measure a wide range of surfaces.

5. Best for Instant TroubleshootingFLIR TG165 Spot Thermal Camera

FLIR TG165 Spot Thermal Camera

With a spot infrared thermometer, you have to measure spot by spot. On the other hand, a thermal camera lets you see the bigger picture, literally.

Instead of measuring just one spot, the FLIR TG165-X shows you the hot and cold spots. This can help you pinpoint trouble spots quicker. Using the built-in laser, you can then target that area to measure the temperature.

Pros

  • 2-in-1 IR thermometer and imager
  • Built-in laser for easy targeting
  • Wide measurement and operating range
  • SD card storage for images
  • Adjustable emissivity

Cons

  • Expensive.
  • No protective case.

Our Review

The large display on the FLIR TG165-X shows you a thermogram. This is a thermal representation of the target area.

Different colors indicate the temperature of different spots. Just by looking, you can tell which parts of the appliance or machine are hot or cold.

If you need the exact temperature of a particular spot, use the included laser to target the IR thermometer. It'll then display the temperature on the screen.

The FLIR TG165 has a 2.4-inch LED display with a brightness of 100 lumens. So, you will not experience any difficulty while using it in low light conditions.

As you measure temperature, you can snap thermal images for later use. You can transfer them to a computer using the included USB cable.

For power, the FLIR TG165-X uses a rechargeable lithium-ion battery.

Issues & Limitations

As expected, a combined IR thermometer and the thermal camera is going to be expensive. If you are shopping on a budget, you'll have better luck with a spot IR thermometer.

For the price, however, it would have been nice for FLIR to include a protective case. To protect your pricey buy, you have to buy the FLIR TG165-X case separately.

Bottom Line

The FLIR TG165-X is the best choice for pros, homeowners, and DIYers who want a thermal camera's convenience and the pinpoint accuracy of an IR thermometer.


6. Best for Cooking & AutomotiveAmprobe IR-730

Amprobe IR-730 Infrared Thermometer

Cooking usually involves very high temperatures, meaning you need an infrared thermometer with a wide measurement range.

We recommend the Amprobe IR-730. It can measure temperatures as low as -26°F (perfect for frozen foods) and as high as 2282°F for things like ovens and grills.

With a 30:1 distance-to-spot ratio, you can measure very hot surfaces from a safe distance.

Pros

  • Extra-wide measurement range.
  • High distance-to-spot ratio – improves measurement accuracy and safety.
  • Adjustable emissivity.
  • Backlit screen withholds, min, and max functions.
  • Includes carry case.

Cons

  • Slightly inaccurate when measuring high temperatures.

Our Review 

In addition to cooking and food preparation, the Amprobe IR-730 is ideal for automotive maintenance and repair, HVAC systems, and other machinery.

It's especially ideal for situations involving very high or low temperatures. Whether you need to check whether frozen food is stored at the right temperature or calibrate an oven, the Amprobe IR-730 is a great tool.

It's also safe to use thanks to the 30:1 distance-to-spot ratio. This is much higher than the usual 12:1 ratio. It allows you to measure very hot surfaces from a safe distance. It also improves accuracy by letting you measure the precise spot you want.

As with most thermal guns, you can adjust emissivity depending on the type of surface you are measuring.

Temperature is shown on a backlit LCD screen. You can engage a hold function where the temperature reading freezes on the screen even after you let go of the trigger.

The Amprobe IR-730 also has min and max functions. Just hold the trigger, and the screen will indicate the highest and lowest temperatures measured.

The Amprobe IR-730 comes with a 9V battery as well as a carry case.

Issues & Limitations 

A common problem encountered by customers is temperature readings that were 5-10 degrees off, especially when measuring very high temperatures.

This is usually not a problem when you are dealing with high temperatures. But if your work requires highly precise measurements, consider another IR thermometer or buy thermocouple probes.

Bottom Line 

The Amprobe IR-730 IR thermometer is a great choice for pros and homeowners who need to measure extra-hot or extra-cold surfaces and objects.

7. Best Budget IR Thermometer For ConsumersKizen LaserPro LP300

Kizen LaserPro LP300 IR Thermometer

If you are shopping on a budget, the best cheap IR thermometer we found is the Kizen LaserPro LP300.

It's cheap but has an impressive measuring range, adjustable emissivity, and high-quality construction backed up by a lifetime warranty.

Pros

  • Cheap.
  • Measures a wide range of temperatures.
  • Adjustable emissivity.
  • Fast response.
  • Lifetime warranty.

Cons

  • No min/max function.

Our Review 

The Kizen LaserPro LP300 is cheap, but that doesn't mean it's inaccurate or poorly made.

With a 12:1 distance-to-spot ratio and adjustable emissivity, it provides the same accuracy as pricier thermal guns.

For its price, the LP300 has a very wide measurement range. It can measure temperatures as low as -58F and as high as 1112F, making the IR thermometer ideal for a wide range of applications, including cooking, HVAC, and automotive.

The LP300 responds very fast; in less than half a second. Just point the gun towards the right spot and press the trigger to get an instant temperature reading.

The display is easy to see and is backlit for easy viewing in all light conditions. When taking measurements, you can activate the hold function that freezes readings on the screen to see the temperature even when you move the gun.

The Kizen LaserPro LP300 comes with a lifetime warranty, longer than you'll get from high-end brands like FLIR. You can be sure it is well made and will last a long time.

Issues & Limitations 

The Kizen LaserPro LP300 lacks a min and max function. This means you cannot record the highest and lowest temperature of an area in one go; you have to keep pressing the trigger to record temperature changes.

Bottom Line 

The Kizen LaserPro LP300 is the best IR thermometer for anyone, including pros, looking for the best bargain on a thermal gun.

8. Best for Home Repairs: Etekcity 1080 Contactless Thermometer

accurate infrared thermometer

Pros

  • Response time of 0.5 seconds
  • Class 2 laser for pointing
  • Temperature range of -50 to 550℃
  • Auto-off feature to save battery
  • Easy to use
  • Holds readings for 15 seconds for recording

Cons

  • Not for humans
  • Battery replacement is difficult

Our Review

With its temperature range of -50 to 550℃, the Etekcity 1080 contactless thermometer is ideal for home repairs. 

Since it has a completely touch-free operation, you can look for any flaws in wiring without risking your safety.

Its UV paint coating helps prevent scratches and chipping off of paint. Its sturdy frame can also withstand daily wear and tear, so you do not have to replace it frequently. 

This Etekcity thermometer has a clear, backlit display, which helps read observations quickly.

It also holds the readings on the display screen for 15 seconds after detection. This helps record the temperature readings while you work. 

Plus, with the laser guide, the Etekcity 1080 thermometer helps you identify the exact spot where you want to measure the temperature.

Its 12:1 distance-to-spot ratio makes it easier to point the laser accurately. 

Issues & Limitations

One issue you might encounter while using this Etekcity thermometer is that it is for inanimate objects only. So it does not give accurate temperature readings for humans and animals.

Changing the batteries is also hard. You have to change it patiently and carefully while following the instructions from its manual.

Bottom Line

To sum up, the Etekcity 1080 contactless thermometer is a remarkable choice for home repairing workers.

It helps you assess the temperature of objects accurately, so there are no weak points in walls once you are done with repairs. Its durable frame also makes sure it does not break on falling. 


9. Best for Automotive Use: SIMOEFFI Touchless Temperature Gun

accurate infrared thermometer

Pros

  • 12:1 distance-to-spot ratio
  • Dual lasers offer a wide range of measurement
  • Easy-to-read white backlit LCD display
  • Adjustable emissivity
  • Pouch for safe storage

Cons

  • Glare in display in outdoors

Our Review 

If you are looking for a multipurpose infrared thermometer, then the SIMOEFFI dual IR thermometer is a great choice.

You can use it in multiple situations, from HVAC checks to automotive inspections. 

The temperature range of -58°F to 1202°F is great for engine and radiator checking. You can also check the temperature in the Celsius scale within a range of - 50°C to 650°C. 

Plus, you can use the small tool bag in the package to store your IR thermometer. You can also keep the Simoeffi thermometer in the bag while traveling to prevent shocks. 

Because it has two laser pointers, you can use the Simoeffi thermometer to cover a range of different points on an object. 

Another great feature is the adjustable emissivity range of 0.1-1.0 that ensures the thermometer can be adjusted for different surfaces. 

Thanks to its 500 ms response time, the Simoeffi thermometer picks up temperature changes quickly and efficiently, which can really save time in a busy auto shop.

Issues & Limitations

The SIMOEFFI thermometer has a practical LCD display, but it can be difficult to read outside / under the sun. Sunlight causes glare, so you need to shield the display to read it properly. 

This IR thermometer is also not suitable for measuring the temperature of humans or animals. So, you will need another option for COVID forehead monitoring. 

The final drawback in an auto repair environment is that high drops can cause this Simoeffi thermometer to stop working, so use it carefully. 

Bottom Line

The SIMOEFFI is a great touchless infrared thermometer for use in an auto repair environment.

Its dual lasers check the temperature of different parts of an object simultaneously. The pouch also helps in carrying and storing the thermometer safely. 


10. Best for Distant TargetsAmprobe IR-750 Infrared Thermometer

Amprobe IR-750 Infrared Thermometer

If you need to measure the temperature of faraway targets, the Amprobe IR-750 has one of the highest distance-to-spot ratios.

You can measure the temperature of a 1" spot from 4ft 2in away.

Pros

  • Ideal for measuring faraway targets.
  • Wide temperature range.
  • Adjustable emissivity.
  • Internal memory.
  • Comes with a thermocouple.

Cons

  • Expensive.

Our Review 

If you need to measure an area's temperature from a distance, because it's either faraway or very hot, the Amprobe IR-750 is the best thermal gun.

While most IR thermometers have a distance-to-spot ratio of 12:1, the IR-750 has a D/S ratio of 50:1. That means you can accurately measure the temperature of a spot that's just 1" wide from 50 inches away (4ft and 2in).

The high ratio combined with the wide temperature range (-58°F to 2822°F) makes the IR-750 a great choice for ovens, grill, and kilns.

You can also use the IR-750 for automotive, HVAC, or electrical work.

And if you need to take the temperature inside an object, the IR-750 comes with a thermocouple.

The IR-750 has a backlit display that's easy to see in a dark and bright environment. Ahold function freezes readings on the screen for 8 seconds while a max and min function displays the highest and lowest temperatures recorded.

Other features include adjustable emissivity and internal memory for up to 99 measurements.

Issues & Limitation 

If you are shopping for a budget thermal gun, we do not recommend the Amprobe IR-750. It is expensive, which is not surprising considering all its features.

Bottom Line 

The Amprobe IR-750 is a great choice for Pros and DIYers who need to stay a safe distance away from the target. It's also ideal for any situation where you need to measure a surface that's hard to reach.

Buying Guide: How to Choose An IR Thermometer

Here are the most important factors to consider when you are shopping for an infrared thermometer.

infrared temperature features

What are non-contact thermometers, and how do they work?

Non-contact infrared thermometers or temperature guns are non-invasive tools for checking the temperature.

They are used to monitor the temperature of extremely hot or dangerous-to-touch objects. 

Infrared thermometers use radiations to assess the object’s temperature. Objects release different kinds of electromagnetic radiation at different temperatures. 

The lens in the infrared thermometer picks out the specific radiation that an object emits.

Then the lens focuses this radiation on a sensor called thermopile that converts electromagnetic radiation into electricity. 

Lastly, another sensor picks up this electricity and converts it into a suitable temperature reading. 

Different Applications of Infrared Thermometers

Infrared thermometers serve many purposes in home and in commercial settings, for example:

Cooking

Cooking is highly dependent on maintaining the right temperature. An IR thermometer helps you determine the temperature of your grill or stovetop without touching it. This helps avoid overcooking or undercooking food, particularly meat. 

Medical Settings

IR thermometers are used extensively in medical settings. They help monitor the temperature of patients with contagious diseases, for example. 

Infrared thermometers are also reliable for checking the body temperature of animals who keep moving. 

Automotive

Mechanics use infrared thermometers to check the temperature of radiators and other vehicle parts. 

Automotive experts rely on non-contact IR thermometers to troubleshoot overheating issues in vehicles. These thermometers are reliable when it comes to checking brakes and tires. 

HVAC

Heating, ventilation, and air conditioning experts need to check for leaks and issues in ducting, plumbing, and electrical systems.

IR thermometers make it easy to identify them by detecting abnormal temperature differences caused by air duct leaks, water leaks, and shorts in the wiring. 

Food Safety

Food workers and manufacturers widely use IR thermometers to ensure food products are maintained at a safe temperature. 

Industrial Settings

Infrared thermometers are used in many kinds of industrial settings, for example, in manufacturing to inspect products and work-in-process for faults, electrical shorts, leaky hoses, and many other defects.  

In chemical processing, IR thermometers are used throughout processing plants in many different ways.

Temperature audits are also useful in product warranty repairs. 

Electrical Work

IR thermometers are helpful for troubleshooting issues with electrical circuits.

Electricians often carry IR thermometers and imagers with them to ensure there are no issues with the electrical wiring and circuits. 

What to Consider When Choosing the Best Infrared Thermometer

Distance to Spot Ratio 

The distance-to-spot ratio tells you how accurate the thermometer is. The typical D/S ratio is 12:1, meaning you can measure a 1" wide spot from 12" away.

A lower D/S ratio means you have to get closer to the target to get an accurate reading, which can be a problem when measuring very hot surfaces.

A higher D/S ratio is generally better as it gets you more accurate measurements and allows you to stay a safe distance from a potentially dangerous surface. However, if you don't plan to measure extremely hot surfaces, don't pay for a higher D/S ratio. For most situations, a 12:1 IR thermometer is adequate.

Accuracy

Accuracy is a major concern when it comes to buying an infrared thermometer. Manufacturers mention the thermometer’s accuracy in plus and minus values. 

Most IR thermometers have an accuracy of +/- 2%, which is fine for most uses. You can also find professional IR thermometers with +/- 1% accuracy, but they are more expensive. 

Temperature Range 

The best temperature range depends on your particular situation. If you often measure extra-hot or extra-cold surfaces, look for an IR thermometer with a wide range.

Some IR thermometers measure only up to around 700F max and -30F min. Others can measure temperatures higher than 2,000F and as low as -58F.

Adjustable Emissivity

An object's emissivity refers to its effectiveness in emitting thermal radiation. For instance, the emissivity of human skin is about 0.98, while that of aluminum foil is 0.03.

You can have two different surfaces at the same temperature but get two varying readings with an IR thermometer because of the difference in emissivity.

For accurate readings, it's important to get an IR thermometer with adjustable emissivity. This lets you adjust the setting as you measure different surfaces.

Display

Look for an IR thermometer with a large and backlit display. A backlit display lets you measure temperature even in dark areas.

Functions

Hold: Holds temperature reading on the screen to give you time to read and record it.

Min and max: Records the highest and lowest temperatures recorded from an area.

Memory: If you'd like to store readings for recording or analysis, look for an IR thermometer with internal memory.

Construction

If you work in outdoor or harsh environments, look for an IR thermometer with a weather-resistant and hardy construction. Ideally, it should have some dust and moisture protection.

If the thermometer doesn't come with a case, make sure you get one, preferably a hard case.


Pros and Cons of Infrared Thermometers

Pros

  • Great for measuring surface temperatures
  • Contactless: can be used at a safe distance from a dangerous environment or contaminated objects/people
  • Great for measuring the temperature of moving objects
  • Measures specific points on a surface (vs. average surface temperature)
  • Compact and lightweight
  • Fast response / readings
  • Onboard photo/video storage

Cons

  • Cannot be used on glass and other transparent surfaces
  • Cannot measure internal temperatures such as cooking meat
  • Not as accurate as some thermal probes
  • Dust, fog, and humidity impact accuracy
  • Sensitive to sudden changes in ambient temperature
  • Can be sensitive to strong electromagnetic fields

Cleaning and Maintaining Your Infrared Thermometer

Infrared Thermometer for babies

Cleaning and maintaining your infrared thermometer regularly is essential for accurate temperature readings. Dust, grime, and debris accumulation will affect the accuracy of your unit. 

To clean your IR thermometer:

  • Gently wipe it with a soft cotton cloth soaked with water or medical alcohol. You should avoid using soap or harsh chemicals to clean the thermometer.
  • Clean the lens first and then move to the rest of the thermometer.
  • Make sure to dry the thermometer fully before taking temperature readings again. 

Store the thermometer in a clean and dry place when it is not in use. 

Most IR thermometers work best when stored at a temperature of 40°F to 100°F. Avoid storing them in more extreme temperatures for extended periods of time. 


Infrared Thermometers: FAQ's

How does an infrared thermometer work?

How to Use An IR Thermometer Properly?

  • Make sure batteries are inserted, and the thermometer is on.
  • Noting the thermometers D:S ratio, hold the gun at the appropriate distance from the target.
  • Check that the laser pointer is resting precisely where you want to measure temperature.
  • Press the trigger button to measure temperature. The reading will be displayed on the screen. Activate hold function (if the thermometer has one) freeze readings on the screen for some time after measuring.
  • If the thermometer has a max and min function, hold the trigger button down to allow the thermometer to record the highest and lowest temperatures.
  • After you've measured the temperature, turn off the thermometer to conserve battery life.

How does an infrared thermometer work?

An infrared collects the infrared radiation from an area and turns it into an electric signal to determine the temperature of that particular spot.

Using infrared radiation allows the thermometer to measure temperature without coming into contact with the target.

How to calibrate an IR thermometer?

You can check if your IR thermometer is accurate by measuring a target with a known temperature or comparing it to the reading from an accurate thermocouple.

However, you cannot calibrate an IR thermometer at home. If you suspect your thermometer is inaccurate, contact the manufacturer to see if they can re-calibrate it.

In most cases, however, IR thermometers come pre-calibrated and don't need to be calibrated again.

Are infrared thermometers accurate? 

The accuracy of an IR thermometer depends greatly on how well you use it. Make sure you maintain the recommended maximum distance from the target and, for human IR thermometers, target the thermometer at the right spot.

Can I use an infrared thermometer to measure human temperature? 

No, you should not. General-purpose IR thermometers are designed only on inanimate objects like the surface of heater coils or a car engine.

If you want to measure human temperature, look for an IR thermometer specifically designed for humans. It'll be more accurate.

Can You Use an IR Thermometer to Measure the Temperature of Liquids?

Yes, you can use an IR thermometer to measure the temperature of liquids like soups. But, to get an accurate reading, you must do a little extra work.

You should stir the liquid thoroughly before taking the temperature reading. This will ensure a consistent temperature throughout the liquid in a container. 

You also have to be mindful of the steam because it can condense and stick to the thermometer and affect accuracy. 

About the Author Rob Carson

I work in commercial construction, in Dallas, TX.

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