In winter the cold outside air contains little vapour. Introducing this air into buildings for airing purposes generally leads to an atmosphere which is too dry.
Situation in winter
For ideal comfort conditions, it will be necessary to supply additional humidity to the premises, either by:
- Water evaporation inside the premises (water and radiator humidifiers).
- Introducing vapour produced by a vapour humidifier (kettle)
Radiator humidifier
Note that the occupants themselves will be a source of humidification through the evaporation of their perspiration. Thus a meeting room or theatre which is poorly aired, can quickly become too humid even in winter.