Dehumidifier for Piano: Why Control High Humidity?

Kevin Busse Jun 23, 2025

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Table of Contents

Humidity and Pianos
1. How Does High Humidity Negatively Affect Acoustic Pianos' Wooden Parts?
2. Pressure Ridges
3. Piano Tuning Instability:
4. Piano Tuner Observations:
5. How Does Excess MoistureNegatively Affect Pianos with Electronics?

Disclosure: Some of the links in this article may be affiliate links, which can provide compensation to me at no cost to you if you decide to purchase.

Grand piano and upright pianos found in rooms with as much as 51% RH (Relative Humidity) can experience damage to both wooden and electronic parts, which should be prevented if at all possible!

Though most damage due to high humidity is no cause for concern, it may have an impact on the appraisal value of the instrument and may warrant replacing electronic components overtime.

It's important to consider placing the piano in an environment free of humidity change and implement dehumidifiers or humidifiers as needed for ideal conditions.

Prevention of significant humidity fluctuations is fundamental when it comes to preserving the health of an acoustic piano. Deciphering the piano's environment is as important as purchasing the right piano for you. The best way to protect your piano is by controlling temperature and humidity levels (sunlight too).

Humidity and Pianos

How Does High Humidity Negatively Affect Acoustic Pianos' Wooden Parts?

If a piano is in a space where the humidity is too high, there will be a few different things that will be negatively impacted.

Here's some of the damages from high humidity:

Pressure Ridges on the sound board
Piano Tuning instability
Pianos will drift sharp when the soundboard swells
Slightly more difficult to tune
Loose glue joints of the action parts
Sticky Keys

Read my review of the GoveeLife Dehumidifier

Read: GoveeLife Dehumidifier Review (Acoustic Piano Maintenance)

Pressure Ridges

These are raised grain lines along the soundboard that make the surface of the soundboard feel like there is a "bump" when you run your fingers across the soundboard. The bump that goes along the grainlines is inconsequential to the sound, though it does mean that the wood fibers have forever been damaged.

Piano Tuning Instability:

A piano room that has humidity above 50% is simply a room that is not humidity controlled. Many piano owners believe that the AC plays a sufficient role to reduce high levels of humidity. As a professional piano technician, using the air conditioner to control high levels of humidity is simply unacceptable.

Piano Tuner Observations:

While tuning the piano, tuners can feel that the tuning pins feel/respond differently in high levels of humidity. This makes stability difficult when setting the pins across the pin block of the piano.

How Does Excess Moisture Negatively Affect Pianos with Electronics?

May effect internal circuit boards
May need to replace circuitboards
Storage facilities must remain dehumidified

A high relative humidity level and electronic components do not mix. The same goes for keyboards and pianos with electronic components.

Replacing circuitboards: Extra humidity due to a variety of environmental factors may be culpable to some extent to the failure of circuit boards. Therefore, replacing select circuit boards may be necessary at times.

Piano owners should take good measure to prevent high levels of humidity in the piano room.

The best way to prevent damage is by operating a dehumidifier in the same room as the piano.

Gel Silica Bead Packs

These packs are only effective for initial/short-term high humidity shocks, and are not protective against sustained high levels of humidity.