Calculation of 
Dew point
- Enter air temperature.
 
- Enter relative humidity.
 
When humid air reaches the 
dew point condensation begins. Saturation pressure and partial
pressure of the steam in the humid air equal when temperature equals the 
dew point.
Mirrors in the bathroom go blind once their surface temperature is below the 
dew point.
Pipes carrying cold water show condensate on their surface when surface temperature is below the 
dew point
of the ambient air. Corrosion is the consequence. Mould formation on house walls is promoted by temperatures below
the 
dew point.