Do you recommend humidifiers for the house or do they simply promote mold?

Depends on variables: Humans function better if the humidity they breathe is within a tolerable zone.For most this is between 35-45%.Above 50% can promote dust mite survival in a home and above 70% will promote mold.Below 30% you often see sore throats, bloody noses and headaches. Humidifiers are often only helpful during the winter when the heater bakes the air and drys it.