Best Thermal Imaging Cameras for Electrical Inspections

Best Thermal Imaging Cameras [2024 Buying Guide]

In this guide, we will take a look at the best thermal imaging cameras for electricians or any engineering professional that conducts electrical inspections or is involved with mechanical systems. We have tested various thermal imaging cameras from various brands and price ranges.

If you’re new to thermal camera imaging technology, you’ll want to be sure to read through our entire guide. Not only will we rank the best thermal imaging cameras, but we’ll also educate you on what you need to know and what to look for before you make a purchase.

What Is a Thermal Imaging Camera?

Before we can answer this question, first we have to understand the concept of thermal imagingThermal imaging is a scientific method of measuring an object’s (or objects’) temperature by utilizing wavelengths of infrared lights. This is why thermal imaging is also often called infrared thermography.

Thermal imaging is a non-contact measurement, meaning we don’t need to directly touch the object to measure its heat/temperature. Instead, this method converts the infrared waves into a visual image that shows different colors. These colors represent different temperatures.

A thermal imaging camera is simply a practical implementation of this technology in a fairly small, handheld camera, which is very useful in the case of electrical inspections and diagnosing mechanical systems.

Since the thermal imaging camera is a form of non-contact measurement, it is easy to use and completely safe. You can easily detect a temperature drop or rise and any hot spots in just a few seconds with this handheld camera.

During electrical inspections thermal imaging cameras are used to pinpoint potential failures in equipment, cables, or systems.

This can prevent power loss, damage, or downtime, which can be more expensive particularly in areas where equipment cannot be shut down. This is also true where physical contact with the equipment is not possible (i.e. due to safety concerns, or in the event that contact might alter its temperature and skew the measurement.)

So, a thermal imaging camera provides two key benefits:

  • Visual way to locate hot or cold spots. Thermal imaging technology allows a very fast measurement of temperature without requiring one to shut down the equipment/system.
  • Safe measurements from a safe distance. Thermal imaging cameras provide the ability to measure temperature without contacting the object from a safe distance. This is important not only to avoid touching hot equipment, but also when dynamic measurement is needed (object is in motion), or it is unsafe to acquire contact-type measurements.

What to Look for in a Thermal Imaging Camera?

There are four key factors to consider when choosing between different thermal imaging cameras:

Resolution 

There are two kinds of resolutions involved in a thermal imaging camera: the resolution of the monitor screen, and the resolution of the detector/sensor. No matter how high the screen resolution is, the image can only be as good as the resolution of the sensor.

The higher the sensor’s resolution, the sharper, clearer, and more accurate a single dot will be on the display monitor, and this will allow us to measure smaller objects from a greater distance.

So, if your operational environment involves the need of measuring equipment from further, you will need a higher resolution in your thermal imaging camera.

Pixel size, measured typically in micrometers (microns) is also important in determining the level of detail produced by the camera. The smaller pixel sizes, the better and the more detail you’ll see.

To summarize, look for the following resolution features in your next thermal imaging camera purchase:

  • high pixel detector resolution, and
  • high display resolution, and
  • low pixel size.

Temperature Range 

Another important consideration is the temperature range of the thermal imaging camera. Imaging cameras that can measure wider and/or higher temperature range will use more expensive sensors, which will translate into a more expensive device.

The best thermal imaging cameras can measure a very wide temperature range from -20°C to 400°C, and there are also imaging cameras that can measure up to 1,200°C.

So, when choosing between different thermal imaging cameras, first check whether the measurement range requirement of your day-to-day application.

Sensitivity 

Sensitivity in thermal imaging cameras refers to how small the sensor/detector can detect differences in temperature.

Devices with higher thermal sensitivities can detect smaller temperature differences, so it can produce an image with greater accuracy. The camera will detect a broader range of temperature differences, producing more colors on the screen.

Sensitivity is measured in mK (milliKelvins), the lower the mK the better and more expensive the camera will be.

Data storage and export

Most thermal imaging cameras can store the measurement data in its built-in memory and removable SD cards, so we can export the stored data to a computer for backup and data analysis/reporting.

Premium thermal imaging cameras might also offer functionalities like Wi-Fi/Bluetooth data transfer to allow direct data transfer to smartphones, tablets, or computers for more versatile analysis and reporting.

Thermal Imaging Camera vs Infrared Camera

It’s important to note that while thermal imaging cameras do involve infrared measurements in how they operate, they are not infrared cameras.

The main difference between the two is how the detection takes place:

  • A thermal imaging camera measures the absolute temperature of the object by measuring the mid-infrared radiation emitted by the measured object. Due to this measurement method, a thermal imaging camera can work in complete darkness since it doesn’t depend on light, and it can work without an infrared beam.
  • An infrared camera (or called active infrared/IR camera) uses short wavelength infrared light (the beam) to illuminate an object/area of interest. It will then detect the reflection of this beam and generate an image. The beam can be mid or long wavelength of infrared. Active infrared cameras are affected by smoke, light interference, dust, etc. while thermal imaging cameras aren’t.

How Accurate are Thermal Imaging Cameras?

Typical thermal imaging cameras can produce an accuracy of +/-2 °C or +/-4°F. This level of accuracy is, in most cases, enough in electrical inspections, but might not be enough in, for example, measuring human body temperatures when a 2°C difference can be very significant (i.e. 36°C is considered healthy while 38°C is not.)

Can I Use My Smartphone as a Thermal Imaging Camera?

This is a great question, and the answer is YES! With thermal imaging cameras becoming smaller and lighter, it would only make sense that the technology would enter the smartphone market.

There are actually two ways we can use our smartphone as a thermal imaging camera:

  1. Getting an actual thermal imaging smartphone with a built-in thermal imaging camera. There are products like CAT S61 Rugged Smartphone with integrated FLIR camera available in the market.

CAT PHONES S61 unlocked Rugged Waterproof 64GB Smartphone with integrated FLIR camera

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2. Getting a thermal imaging phone adapter, which is a detachable thermal imaging detector/camera that we can connect to our smartphone via thunderbolt/micro USB/USB-C.

The option reviewed above is great if you’re also in the market for a new smartphone, as you can get a pretty decent thermal imaging camera while using your phone’s screen as a display for around $500. If you are looking to leverage your existing smartphone then we’ve provided two options below by FLIR

FLIR offers two products we recommend in this category:

#1. FLIR ONE Gen 3 (Android model)

FLIR ONE Gen 3 - Android (USB-C) - Thermal Camera for Smart Phones - with MSX Image Enhancement Technology, 1 Count (Pack of 1)

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Key features:

  • 80 x 60 thermal resolution
  • ±3°C or ±5% accuracy
  • -20°C — 120°C (-4°F — 248°F) temperature dynamic range
  • -20 °C – 60 °C (-4°F – 140°F) non-operating temperature
  • 34 x 67 x 14mm (1.3 x 2.6 x 0.6in) dimensions, 34.5 grams

#2. FLIR ONE Pro (iOS model)

FLIR ONE Pro - iOS - Professional Grade Thermal Camera for Smartphones - with VividIR and MSX Image Enhancement Technology

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Key features:

  • 160 × 120 thermal resolution
  • 70 mK thermal sensitivity
  • ±3°C or ±5% accuracy
  • -20°C — 400°C (-4°F — 752°F) temperature dynamic range
  • -20°C — 60°C (-4°F — 140°F)) non-operating temperature
  • 68 × 34 × 14 mm (2.7 × 1.3 × 0.6 in) dimensions, 36.5 grams

If you are in the market for a more traditional, handheld thermal imaging camera continue reading our comprehensive review below. The thermal imaging device listed are designed with the professional user in mind.

Best Thermal Imaging Cameras

#1. FLIR E5-XT Thermal Imaging Camera (Very Expensive)

FLIR - E5-XT with WiFi & MSX E5-XT - Handheld Infrared Camera - with Extended Temperature Range, MSX Image Enhancement Technology, Wi-Fi & Bluetooth for Instant Data Sharing - (160 x 120)

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Specifications:

  • 160 × 120 IR resolution
  • 20°C to 400°C (–4°F to 482°F) temperature range
  • MSX image enhancement
  • <0.15°C (0.27°F) / <150 mK thermal sensitivity
  • 4 color palettes (Black & white, iron, and rainbow)
  • 640 × 480/55° × 43° digital camera resolution,
  • 9Hz refresh rate
  • 3 mrad FOV
  • 244 × 95 × 140 mm (9.6 × 3.7 × 5.5 in) product dimensions
  • 575 kg (1.27 lb.)
  • Wi-Fi connectivity

 Key features:

  • Radiometric fully-featured imaging camera can take IR and visual images simultaneously not only from the center spot but the full scene
  • 3”, 320×240 LCD screen with 9 Hz refresh rate
  • 27 lbs weight, compact and comfortable to use
  • Built-in image storage with a browsable gallery
  • 45° x 34° field of view with three color palettes

Our Verdict: 

While at first glance the FLIR E5-XT set of features might seem sub-par compared to others in this list, the E5-XT is a fully-featured radiometric camera. Meaning, you get temperature data from the full scene, not only from the center spot like others in this list. It is ruggedized and very durable and is intended for professional use.

#2. FLIR TG165-X Thermal Imaging Camera (More Affordable)

FLIR TG165-X Thermal Imaging Camera with Bullseye Laser: Commercial Grade Infrared Camera for Building Inspection, HVAC and Electrical

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Specifications: 

  • -25°C to 300°C (-13°F to 572°F) temperature range
  • 2 MP (1600 × 1200 pixels) display resolution (TFT display)
  • 80 x 60 thermal resolution
  • <70 mK thermal sensitivity
  • 210 × 64 × 81 mm (8.3 × 2.5 × 3.2 in) product dimensions
  • 51° × 66° FOV
  • Class 1 laser technology
  • 394 kg (13.9 oz) weight

Key features: 

  • Flir TG165-X uses two laser pointers that project onto the object of measurement allowing a more precise measurement of smaller and complex objects
  • Wide horizontal FOV (51°) allowing an easy way to scan your object
  • 80 x 60 thermal resolution is pretty decent for the price, although the included TFT screen is pretty small
  • Six color palettes: iron, rainbow, whitehot, blackhot, arctic, and lava, great for showing color differences

Our Verdict: 

FLIR is obviously one of the most well-known brands in the thermal imaging camera market, and the TG165-X is a very decent entry-level camera from the brand with great value: wide FOV, easy to use, great temperature measurements, and laser pointer functionality.

A key consideration is that the FLIR TG series is not actually a full thermographic camera, but can be thought of as a hybrid between infrared thermometer and an actual thermal imaging camera.

#3. HTI-18 Thermal Imaging Camera (Very Affordable)

220 x 160 IR Resolution HTI Thermal Imager, Handheld 35200 Pixels Thermal Imaging Camera with 3.2" Color Display Screen(Battery Included)

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Specifications:

  • -20 to 300 (-4°F to 572°F) temperature range
  • 220×160 thermal detection resolution
  • 56°x 42° FOV, 0.15mm shortest focal length
  • 70mK thermal sensitivity
  • Fast response time of 0.5 ms.
  • 5 color scale palettes (Rainbow, Iron Red, Cold Color, Black and White, or White and Black)
  • 3 GB micro SD included
  • Weighs only 13.3 ounces

Key features: 

  • 3.2” color display screen with 320×240 thermal detection resolution
  • 56°x 42° FOV, 0.15mm shortest focal length, impressive for its price range
  • Compact and lightweight at just 389 grams with ergonomics design
  • 2” TFT screen with 9Hz refresh rate
  • Can store up to 20,000 images on built-in 3GB SD card

Our Verdict:

A great thermal imaging camera with a premium set of features from the 220 x 1600 thermal resolution to 56°x 42° FOV with a pretty affordable price tag. Ergonomics handle with intuitive menus, making it easy to use. Great for household electrical inspections and due to its high resolution, also great for industrial use.

How Far Can I Measure with a Thermal Imaging Camera?

The spot-size ratio tells us how far we can be from a measurement object and still get an accurate temperature measurement with the thermal imaging camera.

The smaller the pixel size of the detector, the more pixels can be latched onto the target measurement, which will give more details in the produced thermal mage.

On the other hand, the higher the resolution of the camera, the more opportunity to get more pixels on the target. It’s important to note that digital zoom of the camera won’t improve measurement accuracy.

So, in measuring the effective distance of a thermal imaging camera, we should consider three factors: the camera’s resolution, the horizontal field of view of the camera (FOV), and pixel size.

We can calculate the spot/size ratio with the following formula:

Spot/size ratio= IFOV (Instantaneous Field of View) in inches : distance of measurement

While we can measure IFOV with:

IFOV (in mrad) = (FOV / number of horizontal pixels) x [ (3.14/180) x (1000) ]

Then we should convert the IFOV from mrad to inches with the following formula:

IFOV (inches) = IFOV (mrad) / 1000 x measurement distance in inches

For example, if your camera’s resolution is 160 × 120 pixels (160 horizontal pixels) with horizontal FOV of 24-degree, and  you are going to measure an object from 10 feet away (120 inches)

Then, first, we are going to measure the IFOV in mrad with the above formula:

(24 / 160) x [ (3.14/180) x (1000) ] = 2.616 mrad.

Then we are going to calculate the IFOV in inches:

(2.616 / 1000) x 120 = 0.31392 inches

Then we get the spot/size ratio = 0.31392” : 120”

We can then use cross-multiplication to know how far we can accurately measure a 1” spot:

0.31392 : 120” = 1” : X

120” x 1” =  0.31392 x X

then solving for, X  = 120” / 0.31392”

therefore, X = 382.26 inches or 31.855 feet

So, with this thermal imaging camera in the example, we can accurately measure the temperature of a 1” spot from 31.855 feet away.

Some manufacturers list the camera’s theoretical spot size ratio, and you can use the above formulas to calculate the effective distance. All manufacturers should list their FOV and resolution, so you should be able to make the calculations yourself.

Why Thermal Imaging Cameras are Important for Electrical Inspections?

Here are some common applications of thermal imaging cameras during electrical inspections:

  1. Thermal imaging cameras allow us to check for temperature spikes associated with high electrical resistance before the circuit becomes hot enough to cause an explosion and/or outage. We can easily check thermal patterns caused by poor surface contact and multi-phase imbalances causing overloads.
  2. Detect problems caused by switch contacts and connectors by detecting abnormal heat through contact. In these cases, the point of heating may be very small, and a thermal imaging camera is necessary to detect the heat point.
  3. Easily check abnormal temperature differences between different controllers and wires, which can be a sign of an overloaded circuit.
  4. Find equipment/appliances that need replacement easily. In a huge system with hundreds of pieces of equipment, finding a device that is likely to fail can be difficult, but a thermal imaging camera can easily detect the absence of a heat signature.

Best Thermal Imaging Cameras – Final Words

The best thermal imaging cameras that we have shared above are our top recommendations for your next purchase. We hope you’ve gathered enough information from this comprehensive buying guide, and are now better equipped to make an informed decision.