A relative indoor humidity of 40-60% is recommended to create a feeling of comfort and well-being. A hygrometer measures that value and helps to create and maintain an optimum indoor climate.


Woman with children

Problem: how to find out and interpret indoor climate values

While most people know what room temperature is, that is not the case with relative humidity although it is just as important for creating a good indoor climate. A lot of people wouldn’t know whether the air in their home was too moist, too dry or just right.

Relative humidity tells you how moist the air is. It is a ratio that indicates the current level of water vapour (gaseous water) in the air in relation to the maximum possible amount that the air can absorb. The maximum will depend on the current room temperature.

Experts recommend a relative humidity of between 40 and 60% as this creates an atmosphere that the majority of people find to be pleasant. If the value is any higher, there is too much moisture in the air while a value below 40% indicates that the air is too dry. Both are signs of a poor indoor climate and pose hidden dangers to people, furniture and furnishings.

Risks from air that is too dry or too moist

A value that is constantly above or below the recommendation can be damaging to health and property. A hygrometer monitors the indoor climate, enabling you to react in good time if the humidity remains too high or too low for a long period of time. If the air is too moist, i.e. the level of moisture is permanently above 60%, then there is a risk of mould forming. This can affect the health of people who are healthy and particularly people who are at risk and can also cause damage to furniture and soft furnishings. Mould spores in the air and mould on the walls are extremely harmful to health and have to be treated by experts.

Especially in winter, when the air outside is naturally dry and the heating is on indoors, the value can often remain below 40% for a long time. This can dry out our eyes, skin and mucous membranes and lead to colds, respiratory problems, headaches, fatigue and other symptoms.


Little boy who is sick
Hygrometer Selina little in white by Stadler Form


Hygrometer Selina by Stadler Form

The solution: a hygrometer

A hygrometer is in fact a «must-have» for every room. It measures the relative humidity continuously so that you can see the value for each room at any time. You can see if the value changes and take appropriate action if it remains above or below the recommended range for a long period of time. So to prevent mould from forming if the air is too moist, you can get yourself a dehumidifier in good time. And if the value is too low, a humidifier can prevent itchy eyes, colds and other symptoms.

Where a hygrometer is placed can have a negative impact on measurement. It is important for the air to be able to circulate around the measurement device and it should not be placed in direct sunlight or near to any source of heat. Since these stipulations must be observed in order for the results to be correct, it is best to place your hygrometer on a chest of drawers or table rather than on a shelf or directly in front of a window.

There are mechanical and electronic hygrometers. All Stadler Form hygrometers are electronic battery-operated measurement devices so the batteries will need to be replaced when they run out. Both models from Stadler Form measure and display the room temperature as well as the relative humidity. This is displayed as a percentage and indicated by a smiley face. A smile shows that the humidity value is within the recommended 40 to 60% while a sad face indicates that the humidity is either too high or too low. So you can tell how good your indoor climate is at a glance.


Selina little by Stadler Form

Stadler Form also offers a small model: Selina little. She can be placed discretely on a surface or mounted on the wall using the adhesive pad provided.

    • Measures relative humidity level and temperature

    • Smiley shows whether the air humidity is optimal

    • Pocket-size (only 47 mm wide/high)


    Selina by Stadler Form

    Big sister Selina also displays the time but can only be placed on a surface and cannot be mounted on the wall. She is slightly bigger so that you can also see at a glance – and at a distance – whether your indoor climate is OK.

    • Measures relative humidity level and temperature

    • Smiley shows whether the air humidity is optimal

    • Digital clock display


    This video shows you how Selina and Selina little measure the humdity level of a room.