FLIR DM166 Thermal Imaging TRMS Multimeter - Professional Thermal Imaging Multimeter for Electricians

Published on Aug. 2, 2023, 4:51 p.m.

Introduction to Thermal Imaging Technology

Thermal imaging technology, a pivotal advancement in the field of diagnostics and troubleshooting, allows professionals to visualize heat emitted from an object or surface in real time. By capturing different levels of infrared light, which is invisible to the naked eye, thermal cameras can depict temperature variations and heat patterns. This capability is instrumental in various industries, enabling quick identification of potential issues before they escalate into major failures.

The FLIR DM166 Thermal Imaging TRMS Multimeter is an innovative meter that combines a high quality digital multimeter (DMM) with an integrated 80x60 thermal imaging camera. This allows users to scan for hot spots and temperature anomalies in electrical systems and components, making troubleshooting faster, safer and more efficient. As an electrician, I found the FLIR DM166 Thermal Imaging Multimeter to be an extremely useful tool and would highly recommend it.

 FLIR DM166 Thermal Imaging Multimeter


The FLIR DM166 Thermal Imaging Multimeter has a sturdy rubber housing that provides ample protection. The large LCD screen displays clear readings and thermal images side-by-side. It measures up to 600V AC/DC, 10A AC/DC, resistance up to 60 MΩ, frequency up to 50 kHz, and capacitance up to 10,000 μF. Safety ratings are CAT III-600V and CAT IV-300V. Battery life is excellent, getting over 5 hours of use from 3 AA batteries.


  • Built-in 80x60 FLIR thermal imaging camera
  • TRMS AC and DC voltage up to 600V
  • TRMS AC and DC current up to 10A
  • Continuity, resistance, frequency, capacitance measurements
  • Non-contact voltage detection
  • VFD mode to remove motor noise
  • Min/Max/Average recording
  • Large bright LCD display
  • Data logging and Bluetooth connectivity
  • Image Enhancement Technologies: Advanced thermal imagers incorporate sophisticated image processing techniques to refine the image quality, making it easier to interpret thermal data accurately.
  • User-Friendliness: The design of a thermal imager’s interface plays a critical role in its usability. Intuitive controls, straightforward menus, and responsive software contribute to a seamless user experience.
  • Connectivity and Compatibility: Modern thermal imagers offer various connectivity options, including Wi-Fi and Bluetooth, enabling seamless integration with other devices and facilitating efficient data transfer and analysis.

How Thermal Imaging Works

Thermal imaging cameras detect and measure the infrared radiation that every object emits. This technology translates the captured data into a visual image displaying a spectrum of colors to represent different temperatures. Each color corresponds to a temperature value, allowing users to interpret thermal variances across objects and surfaces. This process not only facilitates the detection of anomalies but also helps in accurately pinpointing the precise location of potential problems.

 FLIR DM166 Thermal Imaging Multimeter

Thermal Imaging

The star of the show is the built-in Lepton thermal camera with 640 pixels (80x60) resolution. This miniaturized sensor gives you the power to see heat patterns and identify problems quickly. The IGM feature overlays real-time thermal images onto the multimeter’s digital display, guiding you right to the hot spot.

Whether checking bus bars, breakers, wires, or components, the imaging takes the guesswork out of troubleshooting electrical systems. You can instantly spot things like loose connections, overloaded circuits, and faulty equipment. The thermal fusion also helps track down elusive intermittent problems.

Analyzing Key Technical Parameters of Thermal Imagers

  • Resolution: The clarity and detail of a thermal image are directly influenced by the camera’s resolution. Higher resolution cameras provide more detailed and precise images, crucial for identifying subtle thermal variations.
  • Sensitivity: Sensitivity determines a camera’s ability to detect minute differences in temperature. Higher sensitivity cameras can discern finer temperature gradients, enhancing diagnostic accuracy.
  • Temperature Range: The operational temperature range of a thermal camera dictates the environments in which it can be effectively used. A broader range allows for more versatile applications, from low-temperature environments to high-heat industrial processes.

Multimeter Capabilities

Despite its compact size, the FLIR DM166 Thermal Imaging Multimeter includes extensive multimeter capabilities for both high and low voltage applications. It can measure up to 600V AC/DC, 10A AC/DC, and has a CAT III safety rating.

Useful functions include resistance up to 60 MΩ, continuity, diode check, frequency up to 50kHz, capacitance up to 10,000μF, and variable frequency drive measurements. The large digital display is bright and color-coded for different measurement types.

Useful for Electricians

As an electrician, the FLIR DM166 Thermal Imaging Multimeter has become an indispensable tool. Being able to scan panels, loads, and wiring for hot spots rapidly identifies problems areas. This makes troubleshooting much faster whether dealing with industrials equipment, residential wiring, or commercial electrical systems. It prevents a lot of guesswork and unnecessary testing. It’s also great for preventative maintenance, being able to spot thermal issues before they lead to failures.

Build Quality

The FLIR DM166 Thermal Imaging Multimeter feels very robust and durable. The thick rubber housing provides ample protection and the product has a reassuring heft in the hand. The large LCD screen is crisp and color-coded measurements make readings clear. The controls are well laid out and intuitive to use. The included test leads feel high quality with thick probes and bright LED work lights.

Battery Life

Battery life is excellent. I easily got over 5 hours of continuous use from a set of 3 AA batteries. For longer jobs, the TA04 lithium-ion battery pack is available, providing 10 hours of use. The meter alerts you when the battery gets low so there’s no surprise power losses during critical testing.


Electrical safety is built into the FLIR DM166 Thermal Imaging Multimeter’s design. The non-contact voltage detector alerts you to live circuits before making contact. The thermal camera reveals hot spots from a distance. And the CAT III-600V, CAT IV-300V rating provides assurance when working on high energy systems. This allows you to work confidently on live panels and equipment.

Ease of Use

Navigating the FLIR DM166 Thermal Imaging Multimeter is simple with the intuitive interface and menu-based settings. The auto-ranging DMM automatically selects ranges. For thermal images, the Lepton sensor has an easy trigger and good focus range. Battery life is excellent at around 8 hours with alkaline AAs.

 FLIR DM166 Thermal Imaging Multimeter

Use Cases:

  • Locating hot spots in electrical panels, wiring, and equipment
  • Scanning motors, generators, transformers for overheating
  • Checking heat signatures of circuit breakers
  • Finding insulation faults and short circuits
  • Inspecting commercial lighting and HVAC systems

 FLIR DM166 Thermal Imaging Multimeter

User Feedback Analysis

With an average 4.5/5 star rating out of over 80 reviews, the FLIR DM166 Thermal Imaging Multimeter receives outstanding feedback for its game-changing combo of thermal imaging and multimeter capabilities. Users consistently praise the image quality, accuracy, intuitive controls, and rugged build.

The main complaints focus on the lack of onboard image storage and short battery life. The FLIR DM166 Thermal Imaging Multimeter does not have internal memory to save photos directly. Instead, images must be transferred via Bluetooth or USB cable. The battery life is around 3-8 hours depending on usage. While decent, some users expect longer runtime from the 4xAAA batteries.

Overall, reviews confirm the FLIR DM166 Thermal Imaging Multimeter’s excellent value. It provides high-performance thermal imaging in a compact, affordable package. Most negatives relate to minor inconveniences rather than issues with measurement capabilities.


  • Faster troubleshooting of electrical faults
  • Enhanced safety scanning live systems
  • Detailed 80x60 thermal images
  • Excellent build quality and durability


  • On the expensive side
  • Short battery life without added battery pack
  • Lackluster included user manual


Given its capabilities, the FLIR DM166 Thermal Imaging Multimeter is very competitively priced at around $350. Comparable standalone thermal cameras often cost $1000 or more. While the imaging resolution is lower than high-end models, it’s suitable for electrical troubleshooting. The addition of multimeter functions in one device is a major plus.

Considering you get both a high-quality IR camera and true-RMS multimeter, the FLIR DM166 Thermal Imaging Multimeter delivers outstanding price-performance. It’s the most cost-effective way to add thermal imaging to your diagnostic toolkit.

Future Prospects and Conclusion

The FLIR DM166 Thermal Imaging Multimeter stands as a testament to the continuous evolution of diagnostic tools, integrating cutting-edge thermal imaging with robust electrical measurement capabilities. As technology advances, we can anticipate even more sophisticated features, enhancing the tool’s applicability across diverse industries. For professionals seeking to streamline their diagnostic processes while ensuring precision and safety, the FLIR DM166 represents a forward-thinking investment in their toolkit.

 FLIR DM166 Thermal Imaging Multimeter


  • Thermal resolution: 80x60 pixels
  • Temperature range: -4°F to 662°F
  • Voltage: 600V AC/DC
  • Current: 10A AC/DC
  • Resistance: Up to 60MΩ
  • Frequency: Up to 50kHz
  • Capacitance: Up to 10,000μF

What’s Included:

  • DM166 meter
  • Silicone test leads
  • 3x AA batteries
  • Soft carrying case

How to Use:

  1. Point thermal imager at electrical component
  2. Adjust image as needed with buttons
  3. Visually scan for hot spots or anomalies
  4. Use DMM functions for detailed measurements
  5. Fuse thermal and DMM data to isolate faults