Withings Thermo review: the hottest smart thermometer you can buy

Withings Thermo




Ease of use




Value for money



  • Simple to use, fast measurements
  • Clinically accurate (FDA cleared)
  • Quality made
  • WiFi or Bluetooth sync
  • 2 year battery life


  • Pricey
  • Mandatory to use app to set it up


Withings Thermo has been around since 2016 but it is finding more use now than ever. The current coronavirus pandemic has brought to the forefront the need for proper hygiene. Taking your temperature with a device that doesn’t even touch you is as sanitary as you can get.

Contactless thermometers were in the past reserved for hospital settings. It is only in the last few years that advances in technology have allowed for their mass production at low cost. Sometimes the best tech advancements are seen in the simplest of things.

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The French outfit is a wearable tech pioneer with origins dating back to 2008. There were few such companies back then, many of them are non-existent today.

Withings devices are known for breaking new ground and are characterized by reliability, accuracy and excellent hardware. Thermo is the first smart thermometer to be cleared by the US Food and Drug Administration (FDA) – one of many firsts for Withings.

I’ve been testing the gadget for the past few weeks. Read on for my Withings Thermo review.

How to set up
How to use
The app

Withings Thermo review: Design

In the box Thermo comes with the unit itself and a little instruction booklet. That’s it. There are no cords, charging hubs or any other gear – that’s because you don’t need anything else.

Instead of plugging in to refuel, the thing is powered by two AAA batteries. It surprised me a little but when you think about it, this does make sense. I’d rather something that is not too power hungry work two years with batteries inside, than add another to the long list of devices I charge on a regular basis.

A nice touch is that the batteries are already inside Thermo so there’s no need for you to bother with this. It means the thing is ready to work right out of the box.

Withings Thermo review: the hottest smart thermometer you can buy

Like all Withings products, the smart thermometer has a sleek design. The edges are smooth and it feels really quality made. There’s only a white color with a removable green protective top, so I’m afraid no color options for this one. The cap is useful for keeping the technology inside clean and to stand the unit up when not in use.

A single physical button can be found in the middle of the device. That is used to switch Thermo on/off and assign the readings to a particular person after a measurement.

Next to the button is a digital display that seemlesly blends into the casing. It shows your temperature measurements in an illuminated dot matrix format. There’s a little LED next to it which lights up in green if your temperature is normal (based on the age of the user), amber if it is elevated and red if it is high.

The device is Bluetooth Smart Ready and has support for Wi-Fi. Inside are 16 Thermopile array sensors (infrared sensors) which take over 4,000 measurements to find the hottest spot on the side of your head. Withings calls this “HotSpot Sensor Technology”.

The device measures from the temporal artery as this is considered the best place to detect temperature changes. The reason is that blood that circulates there comes from the core of the body.

Withings Thermo review: the hottest smart thermometer you can buy

The thermometer itself is extremely portable. Measuring 116m in leghth, 33.2mm in diameter and weighing only 75 grams (including batteries), it can fit into a pocket and reside in a bag or rucksack without taking up much space. And because there are no cables or chargers, there’s no need to carry other gear.

As far as whether you can trust the readings, the smart thermometer has been “cleared” for use by the US Food and Drug Administration (FDA). What this indicates is that the FDA considers Thermo to be substantially equivalent to other temporal thermometers available on the market.

So this should not be confused with FDA “approval” which is required for high-risk medical devices. The FDA clearance means that the device works just as well as other devices on the market which measure temperature from the temple.

As far as accuracy, Withings says Thermo’s readings are within ±0.2°C (±0.4°F) as compared to the rectal equivalent temperature. The range the thing can measure is between 35°C – 43.2°C (95°F – 109.8°F).

Withings Thermo review: How to set-up

As with most connected gear, you will need to do a short setup process by downloading an app to your smartphone. Installation is not done through the Health Mate app which is used for all other Withings devices. Instead, there’s a separate app called Thermo. It works for iOS 10+ and Android 6.0+.

This is in order to accommodate the added functionality the separate app brings. The device can be used by up to 8 people and it will track all of their readings. You set up a profile for each person which makes it convenient to keep tabs on the health of the whole family and if needed share the info with doctors.

Withings Thermo review: the hottest smart thermometer you can buy

Having said that, your personal readings will sync and appear in your Health Mate app. This way that app acts as a central repository for readings for all your devices. For example, I also use a Withings blood pressure monitor and its Sleep Analyzer and everything including Thermo readings appear in the Health Mate timeline. Just make sure when setting up to use the same login-in details for both apps, otherwise they won’t sync. The same is the case for the website dashboard.

You can also tie the temperature tracking app to Apple Health. This is done through the settings screen.

Withings Thermo review: the hottest smart thermometer you can buy

The installation process is seamless and takes no longer than a few minutes. Just follow the instructions to install and pair Thermo with your smartphone. This only needs to be done once.

You can, of course, set it to do measurements either Celsius of Fahrenheit. It is worth mentioning, you can’t use Thermo without installing it via the app first. But this is only required at the start. From that point on there is nothing that requires you to open the app as the temperature readings show on Thermo itself.

Withings Thermo review: How to use

Withings Thermo review: the hottest smart thermometer you can buy
scan straight across to the hairline

If you thought that was easy, it’s even simpler to take a measurement.

Press the single physical button to switch Thermo on and you will see a moving line on its display showing it is ready. Bring it close (about 1cm) to the middle of your forehand and slowly scan straight across to the hairline. In a second or two the device will vibrate twice letting you know it is finished.

Oh, and don’t forget to remove the protective cap before taking your temperature! I forgot to do this once and kept wondering why the message “retry” kept popping up…

You’ll then see your reading on the device’s display. To the right of it is a vertical line. Swiping up and down on this touch sensitive zone scrolls through all the users names.

When you find the right person press the button again and the reading will make its way to the phone automatically via WiFi (if you’ve entered the info during setup) or Bluetooth. I suggest you take the time to enter the WiFi details during setup. This ensures the measurements will find their way quicker to the cloud and it is less straining on battery life.

Withings Thermo review: the hottest smart thermometer you can buy

The fact that it’s so effortless to take a reading makes the device very useful for tracking the temperature of toddlers or children. Because its so quick and easy you can keep a log their temperature multiple times a day while they are sick.

If you forget to assign the reading to a particular person, no worries. When you open up the app, it will prompt you to match all the unassigned readings to the appropriate individuals. Or delete them.

On the odd occasion, I would find the device would fail to take a reading. But that happened perhaps once out of 10-15 times. Simply repeat the process and a couple of second later you should see your temperature measurement.

What’s also useful is that the LED shows color coded feedback. That way you will be sure to notice if your temperature reading is out of whack.

Withings Thermo review: The app

You don’t really need to open the app very often. The device will remember measurements and you can scroll through them on its display. The benefit of using the app is that you can find more info on readings, a longer timeline and advanced health info.

Withings Thermo review: the hottest smart thermometer you can buy

When you open the smartphone software you’ll be presented with a screen allowing you to choose a user name. Click on this and a timeline of their measurements will show up. The last reading shows an arrow which tells you the trend.

The app also allows you to set up reminders and presents this information in a nice calendar view, color coded to show whether you had a normal, elevated and high temperature on each day.

You can also enter comments, medications and even photos for any reading and users. This can be helpful in figuring out whether a particular treatment or medications are having the desired effect.

Withings Thermo review: the hottest smart thermometer you can buy

Apart from the smart functionality, what makes Thermo different from traditional thermometers is that it requires no contact with the body or bodily fluids. It is a totally hygienic way to take a temperature.

Plus it doesn’t need to be cleaned between measurements. Having said that, you can and probably should do this once in a while in order to remove any residue. This is done by taking a cotton swab with rubbing alcohol and gently twirling it on the lens located inside the green probe.

Withings Thermo review: The verdict

I found Thermo to be much quicker and comfortable to use than its traditional counterparts or in-ear thermometers. It is an ultra-hygenic way to take a temperature that integrates seamlessly into the Withings ecosystem of health products.

What I really like is that once you are past the setup process, you can use it with or without the app. It makes getting a quick reading very easy, even with babies when they are asleep.

Using the app has benefits in terms of the additional info and log of readings. The fact that you can set up multiple users makes it ideal to track the health of your whole family during COVID-19, even on a daily basis. The Thermo app will act as a repository for all this information.

Withings Thermo review: the hottest smart thermometer on the market

Withings Thermo
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I have started using Thermo as reassurance during the coronavirus pandemic. I check my temperature at least once a day. All it takes is a few seconds. Everything is uploaded to the cloud without me lifting a finger.

All in all, I found that Thermo works really well. A no hassle device that is there when needed. Its price is a little higher than the simpler options, but you are getting extras in terms of the connectivity and the smartphone software.

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Marko Maslakovic

Marko founded Gadgets & Wearables in 2014, having worked for more than 15 years in the City of London’s financial district. Since then, he has led the company’s charge to become a leading information source on health and fitness gadgets and wearables.

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