Black & Decker Thermal Leak Detector

A good and possibly fun way to help you conserve energy and money


Black & Decker Thermal Leak Detector

With the heating season just around the corner the thrifty homeowner will be looking for ways to keep the cold from infiltrating into the house - while minimizing the amount of heat and cash from seeping out. Black and Decker's non-contact Thermal Leak Detector (TLD100) makes the job easier, and more entertaining.
The TLD100 is a simple device that uses an infrared sensor to determine surface temperatures. There isn't much you need to do; basically you turn the unit on, aim it, press the trigger, and voila, you get a temperature reading.
The TDL100 has an ergonomic pistol-grip design, weighs only 16 ounces, and is made of a high impact ABS plastic. The 1" x 1" screen is reasonably legible (even more so in dim or dark rooms), and it displays both a reference temperature and the scanned temperature. You can switch from Fahrenheit to Celsius simply by flipping a switch located in the battery compartment. It also displays the status of your battery power on the screen. I'm always forgetting to turn things off, so I was glad to see that the unit has a 10 minute auto shut-off feature, particularly since it uses a more pricey 9V battery (not included). I did find that the TDL100 drains the battery power rather quickly. A shorter auto shut off, 3 or 5 minutes, might help extend battery life.

Power switch at top and threshold selector switch
LCD screen showing reference temperature at top of screen and scanned temperature at bottom of screen
The on/off button is located on the front of the unit, below the display screen. Just below the power switch is the threshold selector switch. On the back of the unit are two round windows. The large one at the top projects a coloured spot (green, red or blue), while the smaller one underneath is the infrared sensor, which measures surface temperatures.
When you turn the unit on, the sensor initially takes the temperature reading at whatever you are pointing it at. This is called the reference temperature. You'll see this temperature reading on the top right of the LCD screen. The unit also projects a green spot on whatever it's pointed at. Temperature is displayed to 1/10 of a degree, or .1F (the temperature resolution).

Top window projects coloured spot, smaller window houses infrared sensor
Battery compartment, housing switch to convert readings from Fahrenheit to Celsius
As you move the unit (up, down, right or left) it continues scanning, constantly displaying the temperature of whatever it's pointed at on the LCD screen; this is called the scan temperature. While the unit displays readings quickly (under 1 second), you don't want to move the unit too rapidly across the surfaces you're scanning. When the scanned temperature increases above the reference temperature by a specified threshold level, the projected spot will turn from green to red. Conversely, if the scanned temperature falls below the reference temperature, the spot turns blue.
You select the threshold level by moving the threshold selector switch to one of three settings: 1°F , 5°F, and 10°F. You can turn the light off by moving the threshold switch to the very top position, and just use the information displayed on the LCD screen. Bear in mind that the readings you see on the screen can vary by +/- 2.5°F, the inherent accuracy level of this unit (at a temperature of 73°F; as the temperature increases or decreases, accuracy can change by as much as +/-5°F). Black and Decker recommends starting with the threshold switch at the 5°F setting and then moving it to the 1 °F or 10°F settings. I've found that it works best at the 5°F setting.

No heat loss around this stove vent
Over 20°F heat loss from this dimmer switch
The TLD100 has a 6:1 field of view. At 6" from a surface the sensing area will be 1" diameter. For every additional 6" away the sensing area will be an additional 1" in diameter. So, at 8 feet from your target the sensing area will be 16" in diameter. Generally, you want to be closer to smaller targets.
So, what can you use the TLD100 for? Essentially for measuring the temperature of anything within a -22°F to 302°F temperature range. It will show you all the hot and cold spots throughout your house - doors, floors, walls, pipes, ducts, windows and the like. You'll find a lot of other uses for it as well - finding the radiant heat coils hidden under a floor, measuring the temperature of water coming out of a hot water faucet, determining whether deck, fence or wall surfaces are warm enough to be painted or stained, or even measuring the temperature of food that your cooking - as long as the maximum temperature doesn't exceed 302°F. Black & Decker includes a 'Home Energy Repair Guide' that gives you a range of tips on what to do once you've found leaks in your home. You might also want to check out the website The Money Pit, which is chock full of home maintenance and repair advice.
The TLD100 is not only super simple to use, it looks a lot like a blaster from an old Star Trek movie, which might help you to get the kids involved in finding all those energy leaks. A good and possibly fun way to help you conserve energy and money.



  • -22°F to 302°F temperature range
  • +/- 2.5°F accuracy (at room temperature)
  • 0.1°F temperature resolution
  • 1" x 1" LCD screen
  • 6:1 field of view
  • <1 second response time
  • 3 threshold settings: 1°F, 5°F and 10°F
  • 10 minute auto shut-off
  • 16 ounce weight
  • 2 year warranty
  • Includes: Instruction manual, repair guide

Carl Duguay, December 2010
Discover more great woodworking reviews!
Subscribe Now and get instance online access to our library filled with exciting woodworking information.
Continue to stay connected to the latest tool reviews with our bi-monthly woodworking magazines!