What Humidity Does to Your Piano When humidity levels rise in the summer, moisture in the air causes wooden components to swell . In the winter, dry air causes them to shrink . These subtle but powerful shifts affect your piano in ways that impact sound, tuning stability, and overall performance. Some of the most affected parts include: The soundboard – This wooden board amplifies the piano’s tone and is highly reactive to moisture changes. Even a small change in shape can drastically affect string tension. Action parts – Wooden hammers, wipens, and keys can expand or contract, causing friction or looseness. Felt components – Dampers and hammers may absorb moisture and behave inconsistently. Tuning pins – These can loosen in a dry season and shift more easily, causing pitch instability.
Learn the difference between piano tuning, voicing, and regulation—and why all three matter for piano health and sound.