At the Handicraft Museum of Finland a humidification system with ventilation appliances was introduced in 1984, and used for one year. During this time there were no technical problems but the humidifiers of this type were found out to be a severe health risk. The cold water which these apparatuses use favors the growth of bacteria and fungus. There seems to be no way to keep the system clean enough. Instead of the ventilation and nebulization appliances the safe method is to use the steam humidification system, in which water is always heated enough to prevent all bacteriological growth. -- AATA