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Thermal Leak Detector (TLD)

The Thermal Leak Detector is an easy to use hand held tool to indicate where hot and cold leaks are present within a building using a light that changes color. Some examples of use are: scan around a light fixture to determine if ceiling insulation was removed during installation, scan along window and door sills to see where to add weather-stripping, scan where a wall and the floor meet to find drafts that should be caulked, scan an attic door to see if you need to add insulation.

Requirements: The TLD is battery powered and used inside the classroom.
Manufacturer: Black and Decker
Manual: Thermal Leak Detector
Suggested Grade Levels: 5th and above
Suggested Courses: Earth Science, Environmental Science/Engineering
Video Demonstration: (None available at this time)


Switching On and Off (NOTE: The unit will automatically turn off after 10 minutes.)
    • Press the ON/OFF button to turn the unit on.
    • Press the ON/OFF button a second time to turn the unit off.

Setting Threshold for Color Change:

You can change the threshold setting while you are scanning. If the color is changing erratically, try increasing the threshold. If you see a temperature difference on the screen, but the light is not changing color, try reducing the threshold.

    • For detecting small temperature changes of 1º F (0.5º C), move the slider to the 1º mark on the back of the detector.
    • For detecting medium temperature changes of 5º F (3º C), move the slider to the 5º mark on the back of the Detector.
     For detecting large temperature changes of more than 10º F (5.5º C), move the slider to the 10º mark on the back of the Detector.
    • If you do not want the LED spot to change color, move the slider to the top position where the color spots are X-ed out.

Using the Thermal Leak Detector
    • Hold the unit  and aim near the location you want to scan for a draft or thermal leak. This initial aim point will be your reference target.
    • Turn on the power.
    • Keep the unit aimed at the reference target until the green light shines on the target and a Reference Temperature appears on the screen.
    • Slowly scan the Thermal Leak Detector across the area of interest. If the scanned temperature is hotter than the reference temperature by more than the threshold,        the light will turn from green to red. If the scanned temperature is colder than the reference temperature by more than the threshold, the light will turn from green to        blue.


    1. Energy House
        - Students will be able to describe efficiency and conservation measures for the home and explain why they make sense economically.
        - The lesson plan does not indicate to use the Thermal Leak Detector but it can be used to measure areas before and after the insulation is installed.
         - Resources are provided by
            - Teacher Guide and Student Guide
2. Insulation Investigation: Student Guide p. 26 - 28
        -Students will investigate the insulation properties of different materials
        -Resources are provided by
            -Student Guide