Isothermal vs. adiabatic method for air humidification

In isothermal humidification, hot water vapour is introduced into the air, whereby the temperature of the humidified air remains almost the same or increases by a few tenths of a Kelvin at most.

In adiabatic humidification, on the other hand, cold water is usually atomised into fine aerosols, which then evaporate in the air to be humidified. The evaporation energy is extracted from the humidified air in the form of heat. Therefore, adiabatic humidification is always associated with a reduction in temperature, which, depending on the application, can either be compensated by increased heat supply or used specifically for cooling.