Three inaccurate digital thermometers fall short in Which? accuracy tests.

Three unreliable digital thermometers from Beaba, Beurer and Boots have failed to measure temperatures accurately in our tests.
All three thermometers provided readings that would lead users to believe they were cooler than they actually were.

The least accurate thermometer reported temperatures that were 0.7°C cooler. This inaccuracy could delay users from seeking medical attention for a feverish temperature.

Don’t Buy digital thermometers revealed 
Three thermometers repeatedly failed to provide accurate temperature readings across the tests we carried out with them.

Because of this, we’ve made them Don’t Buys. Here are the inaccurate thermometers to avoid.

Boots Bluetooth Enabled Non-Contact Thermometer, £55 
The Boots Bluetooth Enabled Non-Contact Thermometer works by using infrared technology to detect heat radiating from the forehead. It’s a smart device that allows you to store and track temperature readings in an app.

We tested this thermometer 44 times across 11 temperature points and found that the temperatures given were on average 0.7°C too cool. International standards state that thermometers can be out by up to 0.3°C, so this one was more than twice as inaccurate as it was allowed to be.

We retested an additional sample, but the results provided were just as inaccurate.

With the fever alert system in this thermometer set to go off when temperatures of 37.5°C or higher are recorded, this inaccuracy means your child may have a feverish temperature but you won’t be alerted to it. This could potentially delay you from seeking medical attention. 

Beurer FT 95 Non-Contact Thermometer, £40
It’s been confirmed that the specification of the Beurer FT 95 Non-Contact thermometer is identical to the Boots Bluetooth Enabled Non-Contact thermometer described above. Apart from the brand logo on the device, these are the same thermometer.

Beaba Thermospeed Infrared Ear and Forehead Thermometer, £50
This digital contactless thermometer uses an infrared sensor to take a temperature reading without having to touch the skin.

We also tested this thermometer 44 times across 11 temperature points and found that the temperatures given were on average 0.38°C too cool. Standards state that thermometers can be out by up to 0.30°C, so this one was narrowly outside the accuracy standard.

We retested an additional sample, but the results provided also fell outside the accepted limit.

Test modes are available on digital thermometers to allow them to be accurately tested to the official standard. All the thermometers on test were set up in their test modes.

Other issues to be aware of before buying a digital thermometer 
You’ll want to keep an eye out for a CE or UKCA (UK Conformity Assessed) mark on any digital thermometer you buy.

The CE mark is a requirement for many products sold in the European Economic Area.

It shows that the manufacturer has checked that the product meets all safety, health and environmental requirements and complies with EU law.

In Great Britain, the CE mark will eventually be completely replaced by the UKCA mark, which was introduced in January 2021 and will become mandatory in December 2024. Until then, businesses are still able to use the CE mark for products sold in the UK and that’s why we check for it on the products we test.

Digital thermometers are classified as a medical device and the CE marks they carry need to come with a four-digit number linking the product to the organisation (the notified body) that has checked its compliance. Many other products don’t need the four-digit number.

What does a missing CE mark on my thermometer actually mean?
A wrong or missing CE mark doesn’t always mean that your product will be unreliable or unsafe, but it is a warning sign that something could be amiss.

Products need a CE mark or a UKCA mark to be legally sold in the UK, so a product without either should not be on sale.

What makes Which? digital thermometer reviews different
We test thermometers to the medical electrical equipment standard (BS EN ISO 80601-2-56:2017+A1:2020). This is how we determine whether a thermometer is accurate or not.

We also use a mix of lab experts and a user panel made up of members of the public to work out how simple each digital thermometer is to use.

All of the digital thermometers that pass our temperature accuracy tests can be relied on to give you a correct temperature reading when you need one. We give our Best Buy recommendation to products that both pass this test and achieve high scores for ease of use, comfort, convenience and consistency.

What do the retailers say?
We presented our findings to Beaba, Beurer and Boots.

Boots told us: ‘At Boots we take the quality of our products very seriously and all our products are subject to compliance, performance and safety checks before they go on sale. We are confident in the quality of the Boots Bluetooth Enabled Non-Contact Thermometer and would like to assure our customers that our testing is very robust. This product has been appropriately tested for both laboratory and clinical accuracy in accordance with the internationally recognised ISO test (BS EN ISO 80601-2-56). This laboratory test shows the product meets a higher level of accuracy (+/-0.2°C as opposed to +/-0.3°C) than required by the modified version of the ISO standard test (BS EN ISO 80601-2-56:2017+A1:2020) which was used by Which?.’

Beurer told us: ‘We can confirm that the Beurer thermometer FT 95 is manufactured and tested in accordance with British Standards and European standards. It also complies to the EU Medical Devices Directive, the German Medical Devices Act and registered with the UK MHRA. This product has 100% in production testing and is calibrated to the appropriate specifications. Our testing, which is to regulation under a strictly controlled environment, prove that the product does comply to the specifications as published.’

Beaba told us: ‘Our thermometers are tested to the highest standard in line with British and European Accuracy and Safety Requirements. We acknowledge that whilst testing, Which? seem to have a discrepancy in their readings and we are already investigating this alongside having the accuracy double checked with numerous accredited labs across Europe and UK. Beaba is dedicated to maintaining the high quality of their products and supporting Customer Service.’