Updated: June 4, 2015

Digital Thermometer Review: Forehead Thermometer

exergen forehead thermometer Whether caring for yourself or a child, a good thermometer is a critical tool for checking temperatures (an indicator of infection or illness). Digital thermometers have been around for a long time, using electronics to replace the older, more dangerous mercury filled glass thermometers we used in the "old days". Oral and rectal thermometers are still considered the most accurate for most situations, but for speed and ease of use, many people prefer to use other types of thermometers, like ear thermometers or forehead thermometers. In this guide, we will take a look at a leading forehead model, the Exergen Temporal Artery Thermometer -- how does it work, is it accurate, how much does it cost? If you're worried about flu this season, you'll want to know how quick and accurate these things are.
forehead thermometer


How do Forehead Thermometers Work?

digital thermometer Forehead thermometers take a slightly different reading than oral or rectal thermometers. The most accurate temperature reading comes from the heart -- a pretty tough place for most of us to check. The second best place to monitor temperature is from a major artery coming from the heart. The temporal artery, just below the surface of the forehead, has constant bloodflow coming from the carotid artery, so it serves as a good proxy for your body's core temperature. These forehead thermometers slide across the forehead, registering the heat in the underlying temporal artery -- pretty simple concept. Temporal artery thermometers tend to give readings about 1 degree F higher that oral thermometers, similar to a rectal thermometer reading, so you'll want to keep that in mind when checking for a fever (with a forehead or rectal thermometer, a temperature a little below 100F is considered normal).

Exergen Temporal Artery Thermometer - Forehead Thermometer

There are a few different models of forehead thermometers out there, ranging from about $30 to almost $200 for doctor-grade designs, but the Exergen Temporal Artery Thermometer is our favorite, with only a few minor complaints (which we'll get to). In terms of size, it fits comfortably in the hand and is designed for single hand use. It is powered by a single 9V square battery, which is provided in the package. It comes with a plastic cover which protects the sensor head when not in use (see photo at left). Make sure you take the cover off before using -- we read some negative consumer reviews about inaccurate readings which seemed to be cases where they failed to take the cover off (it is semi-clear plastic, so if you didn't know it was there you might not think to remove it). It has an embedded silver ion antimicrobial head -- silver acts as a disinfectant that destroys bacteria like E.coli, so it basically cleans itself. Other than that, you can clean it with a soft cloth or an alcohol swab.

Using the Exergen thermometer is easy. You place the sensor head in the middle of the forehead, push and HOLD the scan button, then slide it slowly across the forehead towards the hairline, keeping constant contact with the forehead. You should hear it beep, several quick beeps, and the red LED light will glow, letting you know it is picking up sensor readings. You release the button when you are done moving the thermometer, then pick it up and read the temperature on the screen. The thermometer will turn itself off after 30 seconds, or you can quickly push the button to power it off manually. That's one thing we really liked about this forehead thermometer -- quick readings. With a digital oral thermometer, we often sat and waited 20-40 seconds or more to get a final reading. With this thermometer, you have an accurate reading in less than 5 seconds. With multiple family members, you don't have to worry about cleaning it like you do with an oral thermometer, so you can check 3 people in 15 seconds. We also liked the fact that you don't have to stick anything inside anybody -- much easier, especially when dealing with small kids, but also just generally more hygenic.



So what's going on behind the scenes here? The sensor is scanning 1000 times per second, checking infrared heat coming from the artery -- and it records the highest temp it finds (those are the beeps you hear). It also measures the ambient temperature (room temperature), and uses a process called "arterial heat balance" to calculate an accurate temperature reading. In terms of accuracy, we consistently got readings within 1/10 of a degree when taking multiple readings. We also got readings that were almost exactly 1 degree F higher than the digital oral thermometer we used to compare with, as expected.

TIPS:
  • Be sure to remove head cover before use.
  • Make sure you swipe the sensor sideways across the forehead, not down the side of the face.
  • Keep sensor in flat contact with forehead.
  • If you are getting low readings, make sure you are keeping the button down the entire time -- the thermometer only scans when the button is held down.
  • If you're dealing with a sweaty forehead from a fever-ridden child (since excess moisture can throw off the thermometer), they advise you to hold the sensor against the neck, just behind the ear lobe, as a secondary location for taking the temperature.
  • Let the thermometer adjust to room temperature for about 30 minutes before using, if you are moving between very warm and cold spaces.
  • Use it a few times on healthy kids so you know how it works and what to expect.


So what are our complaints? It's really just one thing -- it seems like the design should be reversed. When you hold this thing in contact with the forehead, both the control button and LCD screen are turned towards the face, away from you, so you can't see anything. True, it's only one little button, and you should be able to find and operate it without being able to see it, but why not have the button and the screen on the backside of the thermometer so you can see them when taking the temperature? Also, there is no backlight, so you can't read the screen in the dark. Other than that, for about $35 this forehead thermometer is a good investment for most families. It is self-cleaning, no sticking in ears, mouths, or other places(!). It gives quick, accurate readings. And it's handy to use on multiple people. It's become our thermometer of choice. You can also browse the selection of best-selling thermometers at Amazon if you want to see what else is popular.

You can watch a quick video clip of what it looks like..