ADE WS 1500 Mode D'emploi page 36

Information on the dew point
The dew point is a measure for determining the
moisture in the air and is calculated from the
relationship of relative humidity to temperature.
It defines the temperature at which moisture in
the air condenses.
The warmer the air, the more moisture it can
transport. If dew point and temperature are
exactly the same, the humidity is 100% i.e. the
air is saturated and the moisture condenses –
e.g. indoors on walls, outdoors it leads to the
formation of fog or precipitation.
Normal indoor air at 22°C and 40% humidity,
which is generally found to be comfortable,
has – for example – a dew point of approx.
8°C. This information is particularly helpful for
preventing the formation of mould. As soon as
the temperature of e.g. external walls reaches
the dew point or falls below it, moisture will be
deposited; in the long term this can lead to the
formation of mould.
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Hygrometer WS 1500/1501