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A Reliable Digital Hygrometer Will Save You a Fortune

You may have heard of water and humidity based problems occurring to friends and relatives. Bathroom ventilation has broken down, the basement is too humid, indoor air is too dry, and many more cases such as these. How could these potentially expensive problems have been prevented? With reliable and constant wireless hygrometer monitoring of difficult spaces, these problems can be detected before they cause any real damage!

Purchasing hygrometers is difficult. Which brand or type is the best hygrometer? What features should I look for in a hygrometer? Should it be digital or analog?

Well, I am here to help you make the purchasing process easy by introducing you to a ready-to-use, reliable and accurate hygrometer that comes from Finland. Do you know what else comes from Finland? The happiest people of course, do you notice any correlation…?

RuuviTag in a boat. Ruuvi is a Finnish company.
Finland is one the most boat-dense countries in the world. Hygrometers are needed on boats in order to keep them in good shape for a long time

A Digital Hygrometer is the Most Convenient Way to Monitor Humidity

The number of good, digital hygrometers is increasing all the time. With a digital hygrometer, you will get more precise information without the need to be physically present at the location you would like to monitor. We use our phones a lot. And, by receiving humidity readings directly on your smartphone, you can always make sure that the humidity levels are maintained at the correct level.

Also, humidity readings must often be obtained from difficult places. These could be attics, basements, or underneath concrete structures. In other words, in places where you are not casually hanging around a lot. With the right hygrometer, you can receive alarms if undesired humidity levels are reached, and take actions based on these alarms to prevent damages from occurring.

A smart digital hygrometer in a summer house's basement monitoring relative humidity levels.
Basements are cold and humid places. Measuring humidity is important in order to prevent mould from growing into the structures of a house

Hygrometer Apps are Really Important

In the digital world, apps are the key factor behind successful user experience. So, by choosing a digital hygrometer with an easy-to-use and simple application, you will get the most out of your hygrometer.

Features to look for in an app for a hygrometer:

  • Up-to-date data when in range of the hygrometer/hygrometers
  • Graph of the development of humidity
  • Alarms if humidity is not at a desired level
  • Ability to view multiple hygrometers simultaneously

Why is RuuviTag the Best Available Digital Hygrometer?

RuuviTag is a Finnish invention. It is a small environmental sensor which measures air humidity, air temperature, air pressure and movement. RuuviTag sends these measurements wirelessly to Bluetooth devices such as mobile phones.

RuuviTag sends data via BLE, Bluetooth low energy technology. This method is very energy efficient. RuuviTag measures in a refresh rate of a few seconds, but its battery normally lasts  two to three years.

RuuviTags diameter is 5 centimetres (2 inches) making it a true mini hygrometer. In other words, due to its small size, you can place it almost anywhere.

In addition, RuuviTag is a very accurate hygrometer. Its humidity sensor’s typical absolute accuracy is ±2%, 20…80%, 25 °C.

RuuviTag sitting in a Spanish mountain range.
Here is a RuuviTag on a Spanish mountain range

RuuviTag is One the Most Durable Hygrometers

RuuviTag is durable. The basic version of RuuviTag is certified with IP67 which means that it can handle water splashes and a quick submerge in water. The basic RuuviTag’s operating temperature range is -20 °C to +70 °C (-4 °F to +160 °F). The battery inside the basic version is the factor limiting this temperature range. RuuviTag’s internal components can handle temperatures between -40 °C and +85 °C (-40 °F to +85 °F)

RuuviTag Pro is designed to be used in more challenging industrial uses. There are two versions of the RuuviTag Pro. RuuviTag Pro 2in1 and 3in1. RuuviTag Pro 2in1 is IP68 and IP69K certified and its capsule is completely waterproof. With a waterproof capsule, this sensor does not measure air humidity, thus it does not work as a hygrometer. RuuviTag Pro 3in1 on the other hand is IP67 certified. Its operating temperature is between -40 °C and +85 °C.

A smart sensor Ruuvitag placed on top of a traditional sauna thermometer in a sauna.
RuuviTag Pro can even handle the extreme conditions inside a sauna!

Ruuvi Station as a Hygrometer App

Ruuvi Station is our free mobile application. The app is super easy to use. It has the ability to alert you if humidity is not optimal. It also displays graphs for up to 10 days of history, and while in range, you will receive up-to-date information continuously.

Three different views of Ruuvi's mobile application, Ruuvi Station.
Here is a screenshot from the Ruuvi Station mobile application. On the right you can see the dashboard view, where you can view all of your RuuviTag’s measurements at a glance. In the middle you will find all the measurements of a single RuuviTag. On the right side you can see a history graph showing temperature, air humidity and air pressure. The graph is interactive so you can zoom in and out

Ruuvi Gateway Enables Remote WiFi Humidity Monitoring

RuuviTags work with Bluetooth. So, if your mobile device is too far from the sensors, their measurement will not update on the app.

To solve this problem, we have created the Ruuvi Gateway. Ruuvi Gateway has an enhanced antenna, which can hear RuuviTags in optimal conditions from up to 2 kilometres  (1.2 miles) away.

Ruuvi Gateway listens to RuuviTags’ measurements and transfers them to the Ruuvi Cloud. The Gateway transfers the measurement data to the Internet so that you can review and receive humidity measurements wherever you are.

A dashboard of different envirnmental measurements taken with a RuuviTag.
A screenshot from the Ruuvi Station web interface
Graph of humidity altering outside.
A graph from the Ruuvi Station web interface

Ruuvi is a Hygrometer with Thermometer, Barometer and Movement Sensors

Even though measuring humidity is important, other factors are also important to be measured. Since we are usually interested in relative humidity, the other part of the equation is temperature. It is wise to have all of these sensors in the same device.

With multiple sensors, you can use RuuviTags to monitor other important things in your life. And by measuring everything with Ruuvi, you can collect and analyse all the data on the same application. That’s what we call convenient!

Why to use a Digital Hygrometer? – Four Examples of Hygrometer Importance

As mentioned earlier, using a hygrometer can help prevent costly damages stemming from innapropriate air humidity levels.

Humidor Hygrometer in a Cigar Box

Conditions inside cigar storing boxes should be kept at 70% relative humidity and at the temperature of 21 °C (69.8 °F).

In these conditions, cigars will be best preserved. Their aromas and structure will remain unchanged for a long time in these circumstances. If a cigar box is too humid, the cigars will turn mouldy. Conversely, if they are too dry, the cigars will crack. For more information, check out this article.

Greenhouse Humidity Monitoring Ensures Good Crops 

The relative humidity inside a greenhouse should be between 40% – 70% 

Keeping the relative humidity in this range will help the plants to cool down and photosynthesise. In excessive humidity, mould can start to form on plants and their perspiration can slow down. Temperature is a crucial factor in a greenhouse, so Ruuvi is a gardener’s best friend!

You can find multiple greenhouse related blog posts on our blog!

RuuviTag in a smaller greenhouse monitoring the conditions.
RuuviTag inside a greenhouse monitoring humidity and temperature

Indoor Humidity is an Investment for Better Health

Indoor relative humidity should be 35% and 55 %.

In colder regions, heating during winters dries up indoor air. In excessively dry air, our respiratory tract dries and we are more vulnerable to diseases. Keeping air humidity at the right level makes you feel more fresh and healthy. When the relative humidity is too high, our perspiration becomes more difficult. Our perspiration is also called sweating which is our body’s way to cool us down. This is why you feel extra hot in highly humid areas.

Wooden Instruments Require Stable Conditions

Ideal relative humidity for wooden instruments is around 40% to 60%.

Wood is vulnerable against improper humidity conditions. When the environment is too dry, wood will warp which will ruin delicate instruments. If it’s too humid, mould can start to form on the instruments.

How to Calibrate a Digital Hygrometer?

Watch our video on how to easily calibrate a digital hygrometer.


The best hygrometer for you is the RuuviTag.

Here are some of the reasons why you should look no further, and get one or more RuuviTags:

  • It is accurate
  • It is reliable
  • It is durable
  • The hygrometer app is free and easy to use
  • It also has a thermometer, barometer and a movement sensor
  • It comes at a friendly price!

Ruuvi is a Finnish company that strongly believes in open source principles. This means that Ruuvi’s products are made to be secure and can be played with to suit your unique needs. We do not share or sell your information to third party members.

Buy a Reliable And Accurate Wireless Hygrometer
With a good hygrometer, you can save your money and health by monitoring humidity levels in your everyday life.

Buy a Reliable And Accurate Wireless Hygrometer

With a good hygrometer, you can save your money and health by monitoring humidity levels in your everyday life.


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RuuviTag is a Bluetooth sensor that monitors environmental conditions and sends the data directly to your mobile device. The Ruuvi Station mobile app allows you to view real-time accurate measurements and historical graphs. The app also provides customisable alerts to notify you of critical conditions, such as a melting freezer, excessively high bedroom temperatures that could disrupt sleep, or elevated humidity levels in your basement.

Onboard Sensors (4-in-1)

Temperature: °C, °F, K; typical accuracy ±0,2 °C @ 5-60 °C (±0.36 °F @ 41-140 °F).
Air humidity: RH-%, g/m3, dew point; typical accuracy ±3 RH-% @ 20…80 %. Range: 0-95 %.
Air pressure: Pa, hPa, mmHg, inHg; typical accuracy ±1 hPa. Range: 500-1155 hPa.
Motion: Movement counter. Counter is incremented when acceleration exceeds the threshold on any axis.

Operational Conditions

Operating temperature (with stock battery): -20 °C to +70 °C (-4 °F to 158 °F).
Absolute maximum operating temperature: -40 °C to +85 °C (-40 °F to +185 °F).
Housing: IP67, splash-proof, non-condensing location.
Battery: User-replaceable CR2477 (included). Supports extended operating temperature range battery CR2477T.
Battery lifespan: Estimated 12 to 24 months.
Bluetooth range: 5-20 meters (indoor), 20-100 meters (outdoor). The sensitivity of the receiving mobile device’s antenna, obstacles and wall materials affect the range. For increased range, use the Ruuvi Gateway router as a receiver.

App Features

Free and easy: User-friendly free app, signing in is optional.
Android and iOS.
Alerts: Configurable Bluetooth push alerts with customisable messages.
Real-time measurements: Track data in real time.
Historical data: Detailed historical graphs available for up to 10 days (offline).
History export: 10-day history export.
Dashboard: See all your sensors at a glance.
Personalise sensors: Use custom backgrounds and names.
Multilingual: Available in English, Finnish, Swedish, French, and German.


Integrations: Victron Energy, Home Assistant, Homey, and more.
Remote monitoring: When not within Bluetooth range, online remote monitoring is available with the Ruuvi Gateway and Ruuvi Cloud, both sold separately.

Technical Specifications

Data sheet: Download (pdf)
Read more info below:

What is the optimal air humidity level inside a cigar box?

The optimal air humidity level inside a cigar box is 70%. This level of accuracy is only obtainable with a humidor hygrometer.

Why should I buy a hygrometer?

Hygrometers help prevent problems arising from harmful air humidity levels. Mould is a major threat to your health, and to the integrity of structures. Air humidity is hard to estimate without proper equipment, so purchasing an inexpensive digital hygrometer can save you a fortune in the long run.

Which hygrometer is best for me?

RuuviTag is a versatile digital hygrometer that will most likely suit your needs the best. It is small, durable, inexpensive, and yet very accurate. Buy yours now and be amazed at how convenient this little measuring buddy really is!

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