They don't. My father owned a Steinway 6ft grand and never used a humidifier. The issue is to ensure that the wood remains flexible and doesn't dry, crack and flake. That means if you live in a house where you use air conditioners, keep the ai... read more
They need not just a humidifier, but a humidity control system comprised of a humidifier, a dehumidifier, and a humidistat to control them. This will insure that the piano stays within the manufacturer's recommended humidity range. read more
Humidifier: When the humidity is too low, the Humidifier adds moisture to the air inside the piano until the Humidistat senses that the RH level is high enough. Watering Tube: When the yellow light blinks, the watering tube permits you to easily add water to the System. read more