The FLIR TG165 infrared thermometer with thermal imaging camera is a high-end device for measuring temperatures.

In our test we present the device in detail and illuminate all settings and provide many thermal pictures.

Learn more about possible applications and the strengths and weaknesses of this thermal imager infrared thermometer!

FLIR TG165 – Review

First impression, packaging and first use



The FLIR TG165 is an infrared thermometer with a thermal imaging camera. It is equipped with a separate infrared sensor and a thermal imaging sensor.

The device was developed by FLIR Systems, which are well-known for high-quality brand products. It has established itself as a known IR thermometer in the upper price class and has been on the market for several years.



The target group is, in particular, home improvement and craftsmen who are dependent on a fast contactless temperature measurement. Even in production, the additional thermal imagery can prove useful for measurements.

After unpacking you hold a very robust device in your hand which feels high-quality and well thought out. It is not too heavy and not too light for a “pistol device” and the trigger is not to rigid.

Operating elements

Operating elements

Operating elements

In front of the rather smaller display there are four control buttons with one can navigate in the menu and adjust the settings. On top there is a USB port as well as a micro SD card slot under a rubber cap.

Below you will find not only a thread for mounting on an ordinary tripod for digital cameras, but also an eyelet for threading the included trachlaats. If necessary, you can also put it in a generous jacket pocket.

Two sensors and double laser

Two sensors and double laser

As already mentioned, the two sensors are housed in the front, but there is also a double laser system which is responsible for the marking of the measuring spot.

If you press the right button, the unit switches on very quickly and you can start measuring directly.

Pictures and practice test

Calibration and emissivity coefficient

Setting the emission coefficient

Setting the emission coefficient

The FLIR TG165 performs a self-calibration at regular intervals, accompanied by a soft click. However, this can hardly be heard and does not interfere with the measuring activity. The emissivity coefficients can be selected in the menu from rough specifications. The corresponding roughness of the material is also indicated graphically. A completely stepless adjustment in 0.01 steps is also possible which is praiseworthy. In the manual there is even a table listing the emissivity coefficients for commonly encountered materials.

Quality of recordings


Double laser

The most important thing in advance: the measured temperatures are very accurate, not least because of the freely configurable emissivity coefficient, which is always displayed in the lower right corner of the display. Regarding the resolution of the thermal imaging camera (60 x 80 pixels), unfortunately, not so much performance is to be expected. The device operates there rather in the lower field – but serves primarily as a temperature measuring instrument. A video recording is not possible.

At least the pictures are mostly usable. On the PC, of course, they are small. The MSX-Image-Combining developed by FLIR is also not on board at the TG165, but it covers an nice temperature measuring range from 25 ° C to 380 ° C (-14 ° F to 716 ° F).

Hund mit TG165

Dog and TG165

You can also rotate the unit by 90 ° to make a landscape shot. However, the device itself does not recognize this and the fonts in the recordings are correspondingly incorrectly oriented.

Battery, charging and reset

The lifetime of the integrated battery is commendable. The device lasts an average working day when several measurements are taken. The manufacturer states here 5 hours or more, for “normal use”. An automatic shutdown of the device was also integrated in case of inactivity; The intervals can be selected freely. Charging is done via the USB interface. On the way, the supplied power plug adapters provide the USB output for charging. The integrated battery is permanently installed and can only be changed by the manufacturer itself.

flir-tg165-infrarot-thermometer-waermebildkamera-19-automatische-abschaltungIn the test it came unfortunately once to a “freeze” of the device. The data sheet has been helpful since you can perform a hard reset with the “OK” and “Back” buttons. It is possible to format the complete SD card using a menu option. Caution is advised because there is no security prompt.

Save pictures and gallery


By default, the thermal image is continuously updated. Pressing the front-freeze button will freeze the displayed image and press the “OK” button to save the image on the micro SD card. Alternatively, use the “Back” button to return to the thermal image display.

If you want to view the finished recordings, you can go to the gallery via the first menu option. The corresponding symbol is the SD card and in the submenu you have to select the first point again. Somewhat hidden…. Then you can see the recordings with the arrow keys.

Choice of color palettes

flir-tg165-infrarot-thermometer-waermebildkamera-13-einstellung-farbpaletteYou can choose from three different color palettes in the menu:

  • „Grey“
  • „Iron“
  • „Rainbow“







The three palettes cover most applications but have specific strengths. The grayscale display is especially helpful if the TG165 is to be used as a night vision device. Small differences in temperature can not be detected easily, but the thermal image is easy to interpret for humans.


The “Iron” mode is very versatile and is suitable, for example, for measuring in interior spaces, windows and doors. The “Rainbow” color palette maximizes temperature differences by means of strong color transitions. This is especially helpful during technical testing (heating, electrical, etc.).

Technical specifications



The data sheet provides some details about the exact performance parameters of the TG165. The sensor resolution of the FLIR Lepton module is 60 x 80 pixel with a detectable temperature range of -25 ° C to 380 ° C (-14 ° F to 716 ° F). This corresponds to a wavelength range of 8 to 14 μm at a refresh rate of 9 Hz. The FOV of the optics is 50 ° x 38.6 ° (vertical x horizontal). The LCD (2.0 “color display) has a resolution of 176 x 220 pixel.

flir-tg165-infrarot-thermometer-waermebildkamera-07-anschluesseWith a resolution of the temperature in 0.1 ° C steps and an accuracy of

  • ± 3.0 ° C (± 5.4 ° F) in the temperature range of -25 ° to -10 ° C (-13 ° to + 14 ° F) and
  • ± 2.0 ° C (± 3.6 ° F), in the temperature range of -10 ° to 0 ° C (+ 14 ° to + 32 ° F) and
  • (+ 32 ° to + 716 ° F), depending on the value, is ± 1.5 ° C (2.7 ° F) or ± 1.5%

the device is can be seen as “average”.

The built-in optics have a distance-to-measurement-spot ratio (D: S) of 24: 1 at a field of view of 0.04 °.


The mounting thread for a three-pin is a standard ¼ “-20 thread. The device measures (H x W x D) 186 x 55 x 94mm (7.3 x 2.2 x 3.7”) with a weight of 312g (11 Oz.). The built-in rechargeable battery (lithium-ion) has a capacity at 3.7V of 2600mAh.

Internally, the recordings are stored on the SD card in the .bmp format.

Application areas


Water pipes

Infrared thermometers are suitable for the inspection of interior spaces, windows and doors. Real estate owners often struggle with mold contamination in connection with cold walls. Here, the TG165 is particularly handy because it not only provides the temperature of the measuring point, but also graphical information on the spread of cold spots and thermal leaks in windows and doors.

Radiators and other heating systems can also be examined.


Solar panels

The documentation of thermal inspections is uncomplicated, because all images can be stored on the SD card and later reviewed on a PC.

Likewise, electricians can use the TG165 to inspect control cabinets, lamps, transformers, etc. Mechatronics experts will also certainly find versatile applications for this infrared thermal imaging camera.

Last but not least, the TG165 can be interesting for hobbyists due to the low price.

Contents of delivery


The scope of the delivery includes:

  • flir-tg165-infrarot-thermometer-waermebildkamera-23-dreibein-montageFLIR TG165 Infrared thermometer with thermal imaging camera
  • Wearing band
  • Micro SD card
  • AC universal power supply
  • Quick start Guide

It can be worth to purchase a tripod* to acquire better shots as the device wiggles less. It is also possible to obtain the exact same measurement pattern if nothing slips.

There is also a protective bag* available, suitable for the TG165.

Conclusion – FLIR TG165 – Infrared thermometer with thermal imaging camera


flir-tg165If you are looking for a powerful infrared thermometer and want to pay attention to quality, you are well advised with the TG165.

Although the resolution of the infrared image is small, the thermal image primarily serves as an optical viewfinder for the infrared sensor.

Thanks to the integrated double laser, you can immediately see how large the measurement spot is. The battery life is praiseworthy and make the TG165 recommendable as an everyday device for home improvement, builders and technology enthusiasts.