The Ultimate Guide to Thermometer Guns

The Ultimate Guide to Thermometer Guns

By Emily France, Creative Content Curator | Safety Supplier @rapidfiresupplies | People Person | Theatre Type & Arts Supporter.

In 2020 the outbreak of COVID-19 saw a sudden rush of companies, from restaurants to recruitment agencies, investing in a trusty thermometer gun. The promise was that if a person’s temperature reading showed below the feverish 37.8 degrees celsius, then they would be COVID-free and able to enter their workplace or be accepted as a customer into shops.

Thermometer guns can be highly efficient, but only when used correctly. Our ultimate guide will explain what’s going on inside a thermometer gun and give you the dos and the don’ts for using one in a safe, effective way.

Key takeaways:

Are thermometer guns safe to use?

Yes, they are. In the initial growth of thermometer guns as a staple in our high street shops and workplaces, post-lockdown controversy arose about the dangers of using infrared radiation to detect temperatures. Some people urged that thermometer guns can damage the pineal gland (the gland that secretes melatonin which moderates our sleeping patterns) in our brains because of the use of infrared radiation.

Do not worry, this is false!

Not only is the pineal gland so far back in our brains that a thermometer gun would not be able to penetrate it, but the gun does not actually emit much infrared radiation – we do!

Read on to learn more…

How does a thermometer gun work?

Thermometer guns function by detecting the infrared radiation that our bodies are constantly emit. Every object has atoms moving within it, including you, me and every person on this planet – unless you are currently sitting in absolute zero temperature.

When it is cold these atoms inside us move around slowly, however by turning up the heat, they begin to bounce around at a rapid speed.

This, in turn, causes the atoms to emit more infrared radiation, usually we cannot see it because infrared radiation’s wavelength is longer than that of visible light.

Although, if an object gets very (very, VERY) hot, infrared radiation can become visible to the human eye.

  • Thermometer guns work by using a lens to focus infrared light from the person’s forehead to the thermopile sensor inside.
  • This sensor absorbs the infrared, smartly converting it into heat.
  • The heat turns into electricity which enables the device to determine the temperature of the person and shows it on the digital display.

And that’s it, no nasty radiation makes its way into the brains of people who are temperature checked. A thermometer gun is merely detecting information in a similar way to how we can record our voices on a phone, the device collects the data without impacting the subject.

What’s inside a thermometer gun?

A typical thermometer gun is made up of four main components.

Main Circuit baord of a thermometer

The main circuit board is fitted with:

A microprocessor, power supply, thermopile (infrared) sensor and a digital display.

Many commercial thermometer guns also have a laser pointer on the front to help people carrying out temperature checks to correctly aim at a person’s forehead – incorrect aim will lead to a false result.

How to measure someone’s temperature using a temperature gun.

Hold the thermometer gun perpendicular to the forehead of the person whose temperature you are about to take, ensure that they remain stationary throughout.

Each temperature gun has a specific distance needed between the device and the person, therefore always consult the manual of a new thermometer gun for the proper distance. Make sure that you do not touch the sensing area, this should be kept clean and dry in order to be able to effectively scan the infrared radiation a person is emitting.

Themometer reading distance

Readings should be carried out inside if possible or in the shade. The sun can disrupt the reading resulting in someone seeming hotter than they actually are.

If I pass a temperature gun test, does that mean I don’t have COVID-19?

In short, no. The temperature gun can tell the user whether they have a fever, however this is not always a symptom of COVID-19. You may be overheating for an entirely different reason such as the flu, menopause or food poisoning.

On the other hand, a temperature gun reading may be under 37.8 degrees celsius, but the person may have COVID-19. They could be in the early stages of the virus therefore do not display a fever yet, or they could be asymptomatic and risk unknowingly spreading the virus to others.

Let’s round up!

Pros of temperature gunsCons of temperature gun
Non-contact testing reduces the risk of spreading the virus.How and where it’s used can affect the reading (e.g. in direct sunlight).
Extremely easy to use and clean.Close distance is required to accurately obtain a temperature reading.
Displays a temperature reading within seconds.They don’t guarantee that the person does not have COVID-19.

Temperature guns are a fantastic tool and enable businesses to carry out COVID-19 safe procedures in a relatively cheap and simple way. However, caution must still be taken and other measures such as increased hand hygiene and implementing regular lateral flow testing in the workplace should be put in place to truly stop the COVID-19 spread.

Get in touch!

If you have any queries about our thermometer guns or need help purchasing from our website, do contact us via tel: 0333 0150 330 or email:, we are always happy to help.

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