A hygrometer is a measuring device for determining the level of humidity in the air of a room. In this article you'll find all the information you need to know about the various hygrometers available and our advice on finding the right humidity measuring device.

Why use a hygrometer?

Determining the hygrometry measurement, i.e. the level of humidity in the air in a room, is useful in many ways. This measuring device, which is often combined with a thermometer, is an essential instrument in many professional fields, as well as for individuals who want to improve the air quality in their home.
  • In meteorology, a hygrometer is usually used in conjunction with a thermometer or weather station. Equipped with a humidity sensor, it provides essential data on the amount of water in the air and enables temperature forecasts to be made more accurately, as humidity is a major factor in the temperature felt.
  • In farming, hygrometers are an essential accessory for the proper management of crops, harvests and storage.
  • In industry and the food sector, hygrometer-thermometers indicate the temperature and humidity of a location in order to comply with regulation and prevent risks linked to incorrect product preservation.
A hygrometer is also very useful in the home for optimising garden maintenance and watering, adjusting indoor heating or air conditioning, or checking whether it's worth investing in a dehumidifier or mechanical ventilation system. If there's an excessive amount of water in the air in a home, the materials will deteriorate prematurely and mould and fungi can spread. This affects the health of the home's occupants, notably the most fragile individuals. An elderly person, a child or a baby will be more at risk of developing asthma, a respiratory illness and allergies if they live in an excessively damp home. The reasonable cost of a testing device is well worth it when it comes to protecting the health of the people in your home!

More specifically, hygrometer-thermometers are sometimes used by individuals to ensure that specific possessions are kept in the right conditions, such as musical instruments, cigars and pieces of art sensitive to humidity.

The different types of hygrometer

A wide range of humidity-measuring products of varying levels of accuracy and price are available from tool stores and on the internet. Read our advice so you can make a choice based on your needs and how you want to use your instrument.
  • Mechanical outdoor hygrometers
This model, also known as an analogue hygrometer, covers several types of products: metal spring hygrometers and hair hygrometers.

-Mechanical metal spring hygrometer: this type is very easy to use and contains a spring or composite bar that expands or contracts depending on the ambient humidity. They are very affordable, although limited in their accuracy.
-Mechanical hair hygrometer: this type of product contains a natural or synthetic hair that changes length depending on the surrounding humidity. Hair hygrometers are reliable and inexpensive, although they do need to be regularly calibrated.
  • Electronic hygrometers
Often combined with a thermometer, this type of product is more accurate. Practical thanks to its data display screen, an electronic hygrometer gives an idea of the ambient level of humidity in greater detail. Although expensive, they are more accurate and easier to use.
  • Capacitive humidity sensor hygrometers
Of all the humidity measuring products available on the market, capacitive humidity sensor hygrometers provide the most accurate data. A polymer film on a substrate measures the water in the air. However, this type of product can be expensive and requires extensive maintenance, as the sensor needs to be regularly changed to ensure optimal accuracy.

Each category of hygrometer-thermometer therefore has its pros and cons. It all depends on how you use the instrument, how much you want to spend, your humidity problems, etc. A huge range of products is available and you're certain to find a hygrometer that meets your needs. Discover all our products

How do I choose a hygrometer?

Are you looking for a hygrometer but don't know which one to choose among all the brands, prices, models and products available? Below are a few pieces of information and tips on making your choice and finding the most practical device.
  • Price
Hygrometers are available at a wide range of prices. If you want an inexpensive instrument to measure humidity, a mechanical hygrometer is the best fit. However, if you need more accuracy you might have to invest in a more sophisticated product. If your children's health is at risk or you have a baby in the home, it might be worth choosing a more advanced model and opting for a product that also indicates the temperature.
  • Analogue or digital hygrometer?
An analogue device needs to be regularly calibrated. Digital devices are more practical and the screen display makes them easier to use. You don't need to be a hygrometry expert to use this type of product accurately and you can start using it right away. A digital hygrometer also often provides more data: temperature as well as relative humidity, dew point, etc., which can be useful in managing a domestic humidity problem.
  • Calibrating a hygrometer
Some models need to be calibrated. This is the case with hair or metal spring hygrometers and capacitive humidity sensor hygrometers, which need to be calibrated before first use then regularly maintained. If you're not put off by maintaining the instrument, this type of model may be sufficient, otherwise it's best to buy an electronic device.
  • Accuracy
Think about how you'll be using your hygrometer. If the goal is just to get an idea of the indoor humidity in the same way as you might keep an eye on the temperature, a low-end product is enough. However, if you want to measure the risks for your child or baby, or you want to decide whether it's worth installing ventilation or a dehumidifier in a room, more suitable products are available from every brand: just choose one from the models available.
  • Using your hygrometer
If you're practical around the home, maintaining and calibrating your hygrometer shouldn't be a problem. Otherwise, choose a device that's easy to use and displays the measurement on a practical and easy-to-read digital screen. If you're a novice user, it's pointless spending too much on an expensive product that provides too much detail. Choose a simple hygrometer, if necessary combined with a thermometer, to check the quality of indoor air without any excessive maintenance. Choosing the right hygrometer also depends on the amount of humidity. The most accurate hygrometers are suitable for small amounts of water in the air in a room. Read user reviews, choose a recognised brand, ask for advice in the tool department of your local DIY store, carefully read each product's description and compare products and prices.

By following these tips to choose the right product at the right price, you can determine the humidity level in each room, allowing you to protect the health of your home's occupants, particularly your children, with a device that's suitable for you. Checking the humidity both indoors and outdoors should become a habit. Just like measuring the temperature, it's an essential piece of information for your environment and well-being.

A smart hygrometer for comprehensive monitoring

A humidity measuring sensor is sometimes one of the accessories supplied with a smart weather station, along with a thermometer, a wind gauge, etc. The data is gathered and accessible in real-time on your computer or smartphone via an app. This type of product provides more detailed forecasts and shows trend curves based on previous data.
The Netatmo Healthy Home Coach, another very useful product for measuring indoor air quality, also has a humidity measuring feature. Along with measuring CO2, sound levels and temperature, it's an important factor in achieving a good quality of life in your home!

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