This efficient appliance is used to dehumidify the air in typical moist rooms such
as the bathroom, cellar etc., and to diminish the humidity in living-rooms to create
a more healthy climate.
Air humidity
The air in a room is always moist, sometimes more, sometimes less i.e. it contains water,
even if the temperature is less than 0°C. The humidity in the air does not remain the same
throughout the year. It changes with the seasons, rising sharply in the first half of the year,
followed by a gradual decline.
The humidity in the air can be indicated in two ways. The absolute air humidity is mea-
sured in g/m², indicating the volume of water vapour present in a cubic meter of air, inde-
pendent of the temperature. More important for humans (and animals too) is the relative
humidity indicated in %. This value indicates the temperature dependent saturation level
of the air.
For instance, the absolute humidity of saturated air can fluctuate between ~0.3 g (at -
30°C) and ~55 g (at +40°C). The 0.3 g water vapour in the air at -30°C equals a relative
humidity of ~100%, and at +40°C only ~0.6%. Alternatively, foggy air at 0°C has an abso-
lute humidity of only 4.8 g/m3 - a value that equals approx. 28% relative humidity at a
temperature of 20°C. This shows how moist air (fog) can be very dry.
35-50% relative humidity
= (very) dry
50-60% relative humidity
= normal
60-95% relative humidity
= moist (sultry)
The higher the temperature, the more water vapour is held by the air.
Air moisture enters the home through normal ventilation and remains trapped in the
rooms. As the temperature drops in the autumn and winter, the air is unable to hold the
moisture any longer so that high humidity levels become fog.
In the home the moisture in the air condenses on windows and outer walls, i.e at points
that are not adequately ventilated. This results in a deterioration of the air climate in the
home, even resulting in fungal growth on walls and furniture, etc.
If regular and adequate ventilation and/or heating are unable to bring about the desired
results, then the moisture in the air must be reduced with an electric dehumidifier.
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Function and use
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