Full Review: FLIR TG165 Imaging IR Thermometer

FLIR TG165 Back

FLIR TG165 – Part IR thermometer, part thermal camera

UPDATE, May 1, 2015 – The FLIR TG165 is on sale for a limited time for just $399. Save $100!

The new FLIR TG165 Imaging IR Thermometer makes its debut today to the crowds at the National Electrical Contractors Association trade show in Chicago. Part infrared thermometer and part thermal camera, the TG165 pushes the FLIR product line into new territory. As a thermal imaging camera, it allows for fast visual detection of problems. As an IR thermometer, the TG165 provides accurate temperature measurements for areas of concern. Together these functions allow the user to quickly identify, quantify, and record critical temperature data. The FLIR TG165 is best thought of as an infrared thermometer with the ability to visually locate the measurement area. The thermal imaging function eliminates the guesswork of exactly what area to measure, then the thermometer provides the needed temperature. Users familiar with thermal cameras will note that every pixel of a typical thermal image already includes temperature data. So why incorporate an IR thermometer here as well? The short answer is that the FLIR TG165 becomes both more accurate and more affordable through the inclusion of a infrared thermometer. While a dedicated thermal camera like the FLIR E4 starts at $995, the TG165 can give technicians some thermal camera features plus accurate temperature measurement for just $499.

FLIR TG165 Electrical

Electrical Terminals

Key Features

  • Measure over 700 °F (380 °C)
  • 80 x 60 thermal camera
  • 24:1 distance to spot ratio
  • Save and download images
  • Rugged – drop rated to 6 feet

As temperature is such a widely measured parameter of many industries, the FLIR TG165 Imaging IR Thermometer will find no shortage of appropriate applications. Electrical contractors will utilize it to scan for overloaded or malfunctioning breakers and fuses. Electrical connections such as switches, terminals, and joints can be examined for heat patterns indicative of a bad connection. Mechanical contractors and HVAC technicians can look for proper operation of heating and cooling components, including coils, compressors, and controls. The TG165 will even be useful for basic motor and pump diagnostics: overheating is often an early indication of failure. The FLIR TG165 may be useful in some very basic building analysis, but users will find its capabilities limited due to a lack of thermal imaging resolution and sensitivity. The subtle patterns of airflow and moisture would be better diagnosed with a dedicated thermal camera. Even so, the TG165 will find a home in tool belts from facilities maintenance to automotive repair. Any frequent users of infrared thermometers and spot radiometers may find significant time savings with the added imaging functionality. And as with many newer technologies, time and ingenuity will produce entirely new applications for the crossover capabilities of the TG165.


HVAC Coils

Temperature Measurement
Twin lasers flank the infrared thermometer on the face of the FLIR TG165, providing both accurate location and sizing of the measurement spot. This spot is also represented on the 2” LCD display using centered crosshairs. The TG165 offers a wide temperature measurement range of -13 to 716°F (-25 to 380°C), with the ability to see temperature differences as small as 0.1 °C / °F. Response time is excellent, with readings available in about a tenth of a second. The 24:1 distance to spot ratio is also above average, with many current infrared thermometers still using a 10:1 or 12:1 ratio. The greater ratio of the TG165 allows the user the extra convenience and safety of standing further away to measure the same size spot.

Thermal Imaging
The thermal imaging capabilities of the TG165 are powered by FLIR’s Lepton core, the same same impressive quarter-inch thick unit first seen in the FLIR ONE. The resolution of the FLIR TG165 is 80 x 60, for a total pixel count of 4800. Thermal sensitivity (NETD) is rated at 0.15 °C. For most applications this is a sufficient resolution and sensitivity to help users locate targets of interest based on variations in thermal patterns. The TG165 can image target areas up to a temperature of 260 °F (127 °C). While this imaging limit is lower than that of the infrared thermometer, target temperatures can still be measured up to 716° F. The image temperature levels and span are automatically calculated by the TG165, and cannot be adjusted by the user. This will nonetheless provide the desired image results in the majority of circumstances. Two widely used color palettes are available to the user: grayscale and iron. Absent on the FLIR TG165 Imaging IR Thermometer is FLIR’s excellent MSX thermal image enhancement. MSX utilizes a visible light camera to capture details of a target, then adds this data to a thermal image of the same area. This combined image provides a more intelligible picture of the area, especially at lower resolutions as seen here. Since the TG165 is more focused on temperature measurement than thermal imaging though, the lack of MSX will have less impact than it might on a thermal camera of similar resolution.

FLIR TG165 Elements

TG165 Elements: Thermal Camera (top), IR Thermometer (large middle circle), Dual Lasers (left and right)

The 50 degree, wide angle lens of the TG165 gives a broad field of view even at a close range. At just a few feet, most electrical panels, motors, and controls are completely in view. Technicians will use the wide thermal view to locate areas of interest, then take advantage of the small spot size of the infrared thermometer to capture the needed temperature measurements.

Image Output
Images captured on the FLIR TG165 are stored to an 8GB micro SD card in a bmp format. The card will hold thousands of images, and can be upgraded with any commonly available micro SD card. Each saved file includes the thermal image of the area, along with the temperature of the target in the crosshairs. The emissivity setting of the camera is also recorded, providing a reference for the accuracy of the temperature measurement. It is best said that all these items are stored on the image rather than with the image, as no data accompanies the image except a date and time stamp. Unlike images from thermal cameras, TG165 images do not include radiometric data for each pixel. Measurement spots cannot be added later as is frequently done with thermal images.

User Interface
The user interface of the FLIR TG165 is characterized by the delightful simplicity found on other recent FLIR cameras. Four buttons plus the trigger operate all functions. The first stop on the menu allows the user to recall and view saved images directly on the screen. The second option toggles the image palette between grayscale and iron. Emissivity is up next, with four preset options plus the ability to manually set the emissivity according to the target surface. Continuing down the list, the targeting lasers can be toggled on or off, the user can select Celsius or Fahrenheit scales, and the crosshairs can be turned on or off. The auto power off function can be set to operate after one, two, five, or ten minutes. The next menu option allows input of the date and time for better reporting. The final option provides information about the specific TG165 unit, including firmware version, and the most recent calibration date.

FLIR TG165 Fuses

Fuses Under Load

At just over 7” tall, and just over 2” wide, the FLIR TG165 is more compact than even a small thermal camera. It fits nicely in the hand, with a balanced weight, and the same feeling of heft and quality found in other FLIR cameras. To operate the TG165, first depress the power button for three seconds. It starts up very quickly–in a matter of a few seconds. Pull the trigger to activate the lasers and locate the measurement area, found between the two lasers. When the trigger is released, the image will freeze for five seconds, giving the user a chance to review it. Simply press OK to save the image, or press the back button to return to the live imaging view. Images are retrieved from the TG165 Imaging IR Thermometer by connecting the USB cable to the top of the camera then to a PC or Mac computer. Alternately, the SD card can be removed from the device and inserted into a card reader. Either way, the TG165 will show up on the computer as an external disk or device, from which the images are easily copied. The integrated lithium-ion battery charges through the same USB port on top of the camera. A fully charged battery will provide a 8 hours of continuous use, or several days of regular use. In the base of the handle is a standard 1/4 – 20 tripod mount for stable, repetitive measuring. Included with the FLIR TG165 are a lanyard, USB Cable, International Charger (US, UK, EU, AU, CN plug adapters), 8 GB Micro SD Card, and Technical Documentation.

FLIR TG165 Pump Motor

Pump Motor

Final Thoughts
At root the FLIR TG165 Imaging IR Thermometer is a great tool for measuring temperature at a single point. Think of it more as a scaled-up infrared thermometer, rather than a scaled-down infrared camera. That is, while perhaps not a great thermal camera, the TG165 is an exceptional IR thermometer. For some users, a thermal camera like the FLIR E4 or one of its siblings would be a better option, with the greater feature set yielding greater results. Yet the thermal imaging capabilities of the TG165 are a huge help in understanding where a problem is located, after which the thermometer function can be used to measure temperatures and work out a solution. So often with temperature diagnostics, understanding where to measure is the real challenge. The FLIR TG165 removes the guesswork. Thoughts or questions about the FLIR TG165 Imaging IR Thermometer? Please give us a call at (877) 273-2311, or drop us a line at [email protected]

More Information


IR Temperature Measurement
Basic Accuracy ±1.5% or 1.5°C
Range -25 to 380 °C (-13 to 716 °F)
Emissivity 4 Pre-Set Levels with Custom Adjustment, 0.1 to 0.99
Distance to Spot Ratio (D:S) 24:1
Measurement Resolution 0.1 °C / °F
Response Time 150 Milliseconds
Spectral Response 8 to 14 μm
Lasers Dual Diverging Lasers, Frames Temp Measurement Area
Thermal Imaging
Detector FLIR Lepton™ Microbolometer Focal Plane Array (FPA)
Shutter Integrated Automatic Shutter
Image Resolution 4,800 Pixels (80 x 60)
Spectral Response 8 to 14 μm
Field of view (H x W) 50° x 38.6°
Upper Scene Range 127 °C, 260 °F (400 K)
Thermal Imaging Sensitivity 150 mK
Frame Rate 9 Hz
Color Palettes 2 (Grey Scale, Hot Iron)
Saved Image Format Bitmap (BMP) Image with Temperature and Emissivity
General Specifications
Unit Size (H x W x D) 7.3 x 2.2 x 3.7 in (186 x 55 x 94 mm)
Display Type 2.0 inch TFT LCD
Display Resolution (W x H) 38,720 Pixels (176 x 220)
Battery 3.7 V, 2600 mAh Lithium-ion Battery, Rechargeable via Micro USB
Auto Power Off Yes, Adjustable with Disable
Battery Life Hours Typical Use: Five 8-Hr Work Days Continuous Use: 8 Hrs
Certifications CE / CB / FCC / FDA
Memory 8Gb Micro SD Card
Operating Temperature -10 to 45 °C (14 to 113 °F)
Drop Test Designed for 2 Meter, 6.5 Feet
Tripod Mount 1/4 in – 20 on Handle Bottom
Warranty 2 Years Product, and 10 Years Thermal Imaging Detector when registered within 60 days of purchase

2 thoughts on “Full Review: FLIR TG165 Imaging IR Thermometer

  1. Pingback: Hands on Review: FLIR C2 Thermal Camera | Ivy Tools Blog

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