Humidity Control and Your Piano

Much of your piano is wood, which changes size and shape as the humidity in the room rises and falls.  When the humidity increases, wood swells; and when it decreases, the wood shrinks.


When the wood in your piano swells or shrinks, the tuning changes as the string tension goes up and down.  That is why pianos tend to be sharp in the summer and flat in the winter.


Humidity also affects other wooden parts of the piano, including the pinblock, soundboard, and bridges.


Tuning pins are held tight by the wooden pinblock. If a pinblock dries out too much, the piano will not stay in tune because the tuning pins can’t resist the string tension.


Your piano’s soundboard and bridges, which can crack if they get too dry, are critical for good tone and volume.  They can be repaired, but avoiding the problem is a better solution.


You can keep track of your piano’s humidity with a hygrometer (humidity meter).  Both pianos and humans are at their best when the humidity is between 40% and 50%, so you will both benefit.


For long-term humidity control, you might consider installing a Dampp-Chaser system to automatically monitor and control the humidity inside your piano.  Ask your piano technician for more information.