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18 October 2021

Advantages & disadvantages of different types of thermometers

What Is The Best Thermometer?

It can be extremely beneficial to have a trustworthy medical thermometer at home. The ability to properly determine whether or not someone has a fever provides you with crucial information regarding the next stages in their treatment.

There are many different types of thermometers available, both contact and non-contact. Your family’s ages, as well as your own preferences, will help you to decide which one to purchase.

When someone is unwell, the last thing you want to do is rely on guesswork. Here’s a quick rundown of medical thermometers, including how to use them and what their readings imply.

Read on to learn about the advantages and disadvantages of different thermometers.

The different types of medical thermometers

Digital thermometers

Digital thermometers are the most accurate and quickest form of thermometer. The readings are obtained from the underside of the tongue, the rectum, or the armpit. They are widely available in local pharmacies and can be utilised at home or in hospitals.

Electronic ear thermometers

These thermometers take temperature readings using infrared technology. Electronic ear thermometers are less reliable because they might provide an erroneous reading if there is too much wax in the ear. Despite their high cost, they are far simpler to use on newborns and small children, as digital thermometers may be difficult to persuade youngsters to stay still for long enough.

Forehead thermometers

These infrared thermometers are likewise put on the temporal artery and read heat. Digital thermometers are more accurate than forehead thermometers.

Plastic strip thermometers

These plastic strip thermometers can identify if a patient has a fever, but they do not provide precise temperature measurements. They merely serve as a warning that something is awry. To use them, simply lay the strip on your brow.

Pacifier thermometer

These pacifier thermometers are mostly used on newborns above the age of three months. They require the infant to remain motionless for a few minutes, which might be difficult. As a result, the temperature may be incorrect at times.

Glass and mercury thermometers

These mercury thermometers are for taking a temperature in an old-fashioned manner. Normally, you’d put it under your tongue and wait for the temperature to rise, when the mercury stops rising that is your temperature. Unfortunately, because of the potential of mercury poisoning, this method of taking a temperature is not recommended, and you should speak with a healthcare professional before discarding any you may have.

mercury thermometer
digital thermometer

The pros and cons of each type of medical thermometer

Advantages of digital thermometers

  • Temperatures may be read quickly and accurately using digital thermometers.
  • They’re small and portable, and you can even keep the thermometer in your backpack.
  • It’s simple to read the display.
  • A digital thermometer is reasonably priced.
  • They do not need any particular care.

Disadvantages of digital thermometers

  • Digital thermometers have the disadvantage of having dead batteries.
  • Submerging a conventional thermometer in warm, soapy water is simple, but doing it with a digital thermometer is more complicated.
  • Some digital thermometers are more accurate than others.
  • When compared to rectal or oral thermometer readings, these thermometers might have a one or two-degree discrepancy.

Advantages of electronic ear thermometers

  • Many kinds of ear thermometers just take a few seconds to acquire a reading. As a result, it saves time for parents. And, while it is annoying, it only has to remain in the ear for a short time.
  • The ear thermometer, when properly placed in the ear canal, provides a highly precise reading and is thus a trustworthy technique to determine your baby’s temperature.

Disadvantages of electronic ear thermometers

  • For an accurate reading, the ear thermometer must be inserted into your baby’s ear canal. To reach the ear canal, parents frequently have to tug their newborns’ ears and tilt their small heads, a process that most babies find distressing, and which can affect the accuracy of the reading if they wiggle around.
  • If the infant has an ear infection, it cannot be used. If your child has an ear infection or a lot of wax in their ears, an ear thermometer reading might be drastically different.
  • Cannot be used on infants under the age of one year. Because their ear canals are still too tiny, it is not advised for newborns under the age of six months.

Advantages of forehead thermometers

  • It’s simple to use simply put the thermometer on your baby’s temples or brush it across his or her forehead (be sure to read the exact instructions for each thermometer as this may vary slightly). The forehead thermometer is non-intrusive and simple to use, whether your baby is fussing or deep sleeping.
  • The forehead thermometer allows you to quickly take your baby’s temperature. When a forehead thermometer is finished taking a reading, it will emit a beeping sound. With a sick child, time is always of the essence, and this thermometer guarantees you don’t waste any.

Disadvantages of forehead thermometers

  • The forehead thermometer is one of the priciest thermometers available.
  • A variety of readings to get your baby’s true temperature, you may need to take many measurements and average them. This is because the temperature readings may differ based on how the thermometer is swiped. It takes some getting accustomed to for most parents before they can master the skill of choosing an exact temperature.
  • Heat is detected via the forehead thermometer. As a result, changes in the environment may have an impact on its accuracy. Additionally, if your infant is sweating, the accuracy of the reading may be affected.
    • Awarded a Which? Best Buy
    • Easy to use
    • Contactless
    • Suitable for any age
    • Readings in 1 second
    • Accurate measurements
    • Automatic fever alarm
    Add to basket

Baby with strip thermometer

Advantages of plastic strip thermometers

  • The main advantage of plastic strip thermometers is their price.

Disadvantages of plastic strip thermometers

  • Strip thermometers aren’t nearly as accurate as classic mercury glass thermometers, according to the research
  • Parents who use a forehead strip on a kid with a fever may be misled into thinking their child’s temperature is normal in around 4 out of 10 cases
  • If you just have a forehead strip thermometer, allow for a +/-1.5°C error in the temperature measurement and take many measures throughout time.

Advantages of pacifier thermometers

  • Sucking has a calming and reassuring impact on newborns. Some newborns find that sucking a pacifier helps them relax.
  • There is a lower incidence of sudden infant death syndrome when newborns use pacifiers during sleep and naps.
  • The best approach to prevent your baby from a sudden unexpected death in infancy (SUDI), such as SIDS and deadly sleeping mishaps, is to sleep him on his back with his face exposed.

Disadvantages of pacifier thermometers

  • The usage of a pacifier has been related to an increased risk of middle ear infections.
  • Pacifier usage, especially beyond the age of around 4-5 years, increases the risk of dental issues later in childhood, such as a child’s teeth developing out of line.
  • When pacifiers are lost or misplaced, babies can get quite unhappy.
  • Babies may require their pacifiers to fall asleep.
  • If newborns aren’t old enough to discover and replace their pacifiers during the night, they will cry for assistance. When your kid is eight months old or older, you may train him or her to be pacifier-free.
thermometer pacifier
mercury thermometer

Advantages of mercury thermometers

  • Mercury is an excellent heat conductor; therefore, it can measure even very high temperatures
  • It responds swiftly and produces results promptly
  • It expands in a linear fashion, unlike alcohol or any other liquid
  • Because mercury does not quickly evaporate, it is more durable than an alcohol thermometer
  • When compared to alcohol, it is much smaller
  • Because mercury does not wet the thermometer’s wall, the findings can be quite precise.

Disadvantages of mercury thermometers

  • If the bulb cracks and mercury spills out, it is extremely dangerous to humans and the environment
  • Mercury is difficult to remove and can pollute the area where it has spilt
  • It is unable to detect frigid temperatures
  • Its thermal co-efficient is low.

What type of medical thermometer is the most accurate?

Both inner ear thermometer accuracy and forehead thermometer accuracy are excellent, and most devices can measure temperature to within ±0.2°C when used correctly.  For extra peace of mind, search for thermometer types that have a CE Mark to meet the latest British Standards.  CE Marking is the device manufacturer’s claim that their device meets the essential requirements of all relevant European Medical Device Directives. These Directives outline the safety and performance requirements for medical devices in the European Union (EU).

Why do different thermometers give different readings?

Because of basal body temperature, various thermometers can provide different readings, or the same thermometer might give different readings. Your basal body temperature varies depending on how long you’ve been awake, how much you’ve moved if you’ve stood up, and so on. This is why you should measure as soon as you wake up, before you nap, lie in bed for an extended period of time, or get out of bed.

The main differences between contact thermometers and non-contact thermometers (infrared)

Sensors in touch thermometers monitor their own temperature. Contact thermometers use the heat transfer process known as “conduction” to measure the temperature. They require direct contact with the measured object in order to bring the sensor body up to the temperature of the object.

In non-contact measurements, an infrared sensor is used to determine the temperature of an item by analysing the amount of infrared radiation.

When it comes to application advantages, the non-contact infrared thermometer outperforms the contact-type thermometer, because it is non-contact, this means that you can take measurements without disturbing whoever you are measuring.

Although the price of a non-contact thermometer is more than that of a contact thermometer, the non-contact thermometer saves personnel, material resources, and financial resources.

    • Easy to use
    • Readings in 1 second
    • Accurate measurements
    • Automatic fever alarm
    Add to basket

best thermometer for babies, children and adults

The best thermometers for adults, children and babies


Adults can use any thermometer, here are our top thermometers based off your needs.

Best price: Digital Thermometer

Fastest readings: Inner Ear Thermometer

Non-contact: Ear and Forehead Thermometer


For children, you will want to go for either the Inner Ear Thermometer or the Ear and Forehead Thermometer. These are great options because they take fast accurate measurements which won’t disturb the child.


For babies, the Ear and Forehead Thermometer is the best option. If a baby is sleeping and you need to take their temperature without disturbing them, you can use the contactless infrared mode. The thermometer ambient temperature mode is also useful for checking how hot the baby’s milk is.

How to take a temperature correctly

Choose the body part

Oral measurement

The thermometer is inserted beneath the tongue for this procedure. Adults and children aged 4 and above who are able to hold a thermometer in their mouth should utilise this approach.

Rectal measurement

The thermometer is carefully placed into the rectum for this procedure. This is most commonly done with new-borns, but it may also be done with children as young as three years old. Children older than 3 years can have their rectal temperatures taken, although it may be difficult to keep them as calm as they need to be.

Axillary measurement (armpit or groin)

For small infants or people who cannot properly take their temperature orally, the thermometer is inserted under the armpit. This approach isn’t as precise as oral or rectal, but it’s a good initial check. After that, you can do an oral or rectal reading.

green question mark
thermometer inner ear

Inner ear measurement

This sort of thermometer uses infrared heat to determine the temperature inside the ear. Be careful to follow the device’s directions for appropriately positioning the tip for the best results. Ear thermometers might be quicker and simpler to use for older newborns and toddlers. They are not, however, suggested for babies under the age of three months. If your kid has excessive earwax or an earache, they should not be used.

Forehead measurement

Forehead thermometers are also used to measure temperature, although they are less dependable and typically more costly than digital thermometers. They are attached to the temporal artery of the forehead and measure the amount of infrared heat emitted by the head.


There are different thermometers for different situations. The best way to pick a thermometer is to assess your own situation. In many instances, you’ll have to think about the convenience of the person who is taking the temperature as well as the person getting their temperature taken.

Related products

    • Awarded a Which? Best Buy
    • Easy to use
    • Contactless
    • Suitable for any age
    • Readings in 1 second
    • Accurate measurements
    • Automatic fever alarm
    Add to basket

    • Easy to use
    • Readings in 1 second
    • Accurate measurements
    • Automatic fever alarm
    Add to basket

    • Easy to use
    • Accurate measurements
    • Automatic fever alarm
    Add to basket

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