Milwaukee 2278-20 M12 12:1 Infrared Temp-Gun

Published on Aug. 3, 2023, 9:38 a.m.

Infrared thermography, a technology that captures the heat emitted by objects and converts it into a visible image, plays a pivotal role in various industries. From diagnosing electrical issues to ensuring building insulation efficiency, infrared thermometers, like the Milwaukee 2278-20, provide a non-contact means of measuring temperature, offering both safety and convenience. This article delves into the features, performance, and applications of the Milwaukee 2278-20, showcasing its significance in the realm of infrared temperature measurement.

The Milwaukee 2278-20 is a compact yet powerful infrared thermometer gun that runs on the versatile M12 battery platform. With its 12:1 distance to spot ratio, this temp gun allows users to accurately measure surface temperatures from a safe distance. Read on for a detailed review of the features, performance, and usability of this tool.


The Milwaukee 2278-20 M12 12:1 Infrared Temp-Gun is a versatile and durable tool designed for professionals and DIY enthusiasts alike. It operates on Milwaukee’s M12 battery platform, offering seamless integration with other M12 tools. With its 12:1 distance-to-spot ratio, this infrared thermometer allows for accurate temperature measurements from a safe distance. The device boasts a temperature range of -22°F to 752°F (-30°C to 400°C), making it suitable for a wide range of applications. Its rugged construction and user-friendly design make it a reliable and convenient tool for various tasks.

Key Features

  • High Accuracy and Fast Response: The Milwaukee 2278-20 delivers precise temperature readings with a rapid response time of fewer than 150 milliseconds, ensuring quick and reliable measurements.
  • Adjustable Emissivity: The device allows users to adjust emissivity settings from 0.10 to 1.00, accommodating various surface materials and ensuring accurate readings across different applications.
  • Backlit Rotating Display: The thermometer features a backlit display that automatically rotates, providing clear visibility of temperature readings from any angle, even in low-light conditions.
  • Durable Design: Built with a rugged composite housing, the Milwaukee 2278-20 is designed to withstand harsh working environments and accidental drops, ensuring longevity and reliability.
  • M12 Battery Compatibility: The thermometer is compatible with Milwaukee’s M12 battery platform, offering convenience and flexibility for users who already own other M12 tools.

Design and Build Quality

The Milwaukee 2278-20 features a rugged, industrial design consistent with the brand’s other M12 tools. Its durable composite housing feels solid and can withstand jobsite abuse. The backlit LCD display is bright and easy to read from a distance or awkward angles.

Ease of Use

This infrared thermometer is designed for quick, one-handed operation. Just point, pull the trigger, and get an instant temperature reading. The 12:1 distance-to-spot ratio allows you to measure from over a foot away, avoiding hot or hazardous surfaces. The auto-rotating display also makes it easy to read measurements from any angle.

How Infrared Thermometers Work

Infrared thermometers, like the Milwaukee 2278-20, operate by detecting the infrared energy emitted by objects and converting it into a temperature reading. The device’s lens focuses the infrared radiation onto a detector, which then translates the energy into an electrical signal. This signal is processed and displayed as a temperature reading on the device. The 12:1 distance-to-spot ratio of the Milwaukee 2278-20 ensures precise readings from a distance, enhancing user safety and convenience.

Understanding Infrared Thermometers

Infrared thermometers, like the Milwaukee 2278-20, operate by detecting the infrared energy emitted by objects and converting it into a temperature reading. The device’s lens focuses the infrared radiation onto a detector, which then translates the energy into an electrical signal. This signal is processed and displayed as a temperature reading on the device. The 12:1 distance-to-spot ratio of the Milwaukee 2278-20 ensures precise readings from a distance, enhancing user safety and convenience.

Understanding Distance to Spot Ratio (D:S)

The distance to spot ratio (D:S) is a crucial specification for infrared thermometers. It indicates the diameter of the area measured by the thermometer at a specific distance. For instance, a 12:1 D:S ratio means that at 12 inches away, the thermometer measures a circle with a 1-inch diameter. The Milwaukee 2278-20’s 12:1 D:S ratio ensures accurate temperature readings from a safe distance, making it suitable for various applications.

Accuracy and Performance

In testing, the 2278-20 demonstrated excellent accuracy across various surface materials and temperature ranges. Readings were within 1-2°C when compared to a calibrated thermocouple. The 12:1 D:S ratio provides a large measurement area for consistent, repeatable results. Rapid response times under 1 second allow users to quickly scan for hot or cold spots.

Advanced Functionalities

The Milwaukee 2278-20 integrates state-of-the-art image enhancement technologies, ensuring clear and accurate thermal readings. Its user-friendly interface facilitates quick and efficient operation, making it accessible for both professionals and hobbyists. While the device prioritizes standalone functionality, its compatibility with the M12 battery platform exemplifies its integration into a broader ecosystem of tools, highlighting Milwaukee’s commitment to versatile and adaptable solutions.

Fast Response Time

The Milwaukee 2278-20 boasts a rapid response time of fewer than 150 milliseconds, ensuring quick and efficient temperature readings. This feature is particularly beneficial in scenarios where multiple measurements need to be taken in a short period or when monitoring dynamic temperature changes. The fast response time minimizes delays and allows users to obtain real-time temperature data, enhancing productivity and decision-making.

Adjustable Emissivity

The Milwaukee 2278-20 offers adjustable emissivity settings ranging from 0.10 to 1.00. Emissivity is a measure of an object’s ability to emit infrared energy. Different materials have varying emissivity values, and adjusting this setting on the thermometer ensures accurate temperature readings across a wide range of surfaces. This feature is crucial for professionals who work with diverse materials and require precise measurements in different environments.

Backlit Rotating Display

The Milwaukee 2278-20 features a backlit display that automatically rotates, allowing for easy reading of temperature measurements from any angle. This feature is especially useful in tight spaces or awkward positions where viewing the display directly might be difficult. The backlighting ensures clear visibility even in low-light conditions, enhancing the thermometer’s usability in various environments.

Durable Design for Demanding Environments

The Milwaukee 2278-20 is built to withstand the rigors of demanding work environments. Its rugged composite housing is resistant to impacts, drops, and other hazards commonly encountered on job sites. This durability ensures that the thermometer remains functional even in harsh conditions, providing reliable performance and longevity.

M12 Battery Compatibility: Power and Convenience

One of the standout features of the Milwaukee 2278-20 is its compatibility with the M12 battery platform. This means that users who already own other Milwaukee M12 tools can easily interchange batteries, eliminating the need for multiple chargers and battery types. The M12 batteries are known for their long runtime and reliability, ensuring that the thermometer is always ready for use. Additionally, the M12 platform offers a wide range of battery options, allowing users to choose the capacity that best suits their needs.

Applications and Use Cases

This infrared thermometer excels at diagnostic and preventative maintenance tasks. HVAC technicians can quickly find hot/cold spots to troubleshoot systems. Mechanics can scan for overheating bearings, brakes, or exhaust components. It’s also handy for food safety monitoring, inspecting electrical panels, and other industrial/residential applications.

User Feedback

Based on the user reviews and feedback provided, the Milwaukee 2278-20 M12 12:1 Infrared Temp-Gun receives overwhelmingly positive reception for its functionality, durability, and user-friendly design. Here is a detailed analysis of the user feedback:

Performance and Utility: Users have consistently praised the temp gun for its accurate and reliable performance across a variety of applications. From automotive diagnostics to HVAC troubleshooting and industrial temperature readings, the device is noted for its versatility and effectiveness. The mention of its utility in various contexts, including working on vehicles, heating and cooling systems, and even in-home applications like checking dryer temperatures, underscores its broad appeal.

Ease of Use: The feedback highlights the product’s simplicity and ease of operation. The one-handed use, clear display, and quick response time are frequently mentioned, indicating that users find the device intuitive and straightforward. The auto-rotating display feature, in particular, is appreciated for its contribution to the tool’s ease of use, allowing users to read temperatures from any angle without difficulty.

Durability and Build Quality: Users have remarked on the robust construction of the Milwaukee 2278-20, aligning with the brand’s reputation for producing durable tools. The rugged design is mentioned as a confidence booster, suggesting that users feel the tool can withstand the rigors of various work environments without succumbing to damage.

Battery Efficiency: The M12 battery platform receives special commendation for its long-lasting performance. Users report extended use without significant battery depletion, which enhances the tool’s convenience and reduces downtime due to frequent battery changes. The compatibility with the M12 platform is also seen as a plus, allowing users who own other Milwaukee tools to interchange batteries and streamline their toolkit.

Challenges: While the majority of feedback is positive, some users have noted difficulty in obtaining accurate readings on reflective or shiny surfaces. This issue, however, seems to be mitigated by user adaptations, such as covering the surface with a matte tape, suggesting that while the device is versatile, there might be a learning curve for certain applications.

Overall Satisfaction: The high ratings and enthusiastic reviews reflect a general sense of satisfaction among users. The device’s combination of reliable performance, durability, ease of use, and battery efficiency aligns well with the needs and expectations of both professional and casual users, making the Milwaukee 2278-20 a well-regarded tool in its category.

In summary, the Milwaukee 2278-20 M12 12:1 Infrared Temp-Gun stands out in the market for its accuracy, durability, and user-friendly features. Despite minor challenges with reflective surfaces, the overall user feedback is overwhelmingly positive, showcasing the product’s value and effectiveness across a range of applications.


  • Accurate and fast measurements
  • Durable construction
  • Large 12:1 distance-to-spot ratio
  • Rotating backlit display
  • Runs on Milwaukee M12 batteries


  • Difficult to measure shiny surfaces
  • Higher cost than basic IR thermometers

Conclusion and Future Outlook

The Milwaukee 2278-20 stands out for its precision, durability, and user-centric design, representing a valuable investment for professionals and enthusiasts alike. As technology advances, we anticipate further enhancements in infrared thermography, increasing the accuracy and applications of tools like the Milwaukee 2278-20. Embracing such innovations will continue to transform industries, offering new insights and efficiencies in temperature measurement.


  • Accuracy: ±2% of reading or ±2°C
  • Emissivity: 0.10 to 1.00 adjustable
  • Response Time: 150ms
  • Operating Temp: 0°F to 122°F

Box Includes

  • IR thermometer
  • 9V battery
  • Carrying pouch