A stable relative humidity (RH) is one of the most important factors in keeping your piano in tune. Maintaining a proper RH is also beneficial to other parts of the piano, such as preventing cracks in the soundboard, keeping the tuning pins tight and preventing rust on the strings.
In Montana, we don’t typically have high enough RH to worry about rust or other problems associated with excess moisture in the air. However, we do have enough variation in the RH that it can cause your piano to go out of tune with a seasonal change and, especially in winter, it can get dry enough to worry about the potential for cracks in the soundboard to develop.
An RH of anywhere from 30% to 50% can be good for you and your piano, but evenness is the key to tuning stability. In the drier months, this can be accomplished with a room humidifier or whole house humidifier unit on your furnace. In the warmer months, when spring and summer rains are bountiful, the humidity will be higher and air conditioning will keep the indoor RH levels in check. Many people in Montana don’t have AC, and it is common to cool the house by opening windows at night and close up the house during the day, but be aware this will pull in moisture from outside and will have an affect on the tuning of your piano.
The other solution is to install a Dampp-Chaser Humidity Control System on the piano itself. These systems consist of a humidifier, dehumidifier(s), and a humidistat to cycle between the two to maintain a moisture level in the immediate environment of the piano.
Jeff Stickney is a Certified Dampp-Chaser Installer, and can assist you in determining what solution would be best for your situation. Click here for more information on the PTG website about humidity control, and click here to go to the Piano Life Saver website for more information about the Dampp-Chaser Humidity Control System.