The Silent Killer of Acoustic Guitars and How to Save Yours (Humidity Guide)

While many guitar owners are aware of the dangers of low humidity, it’s just as important to understand the risks associated with high humidity. A guitar becomes over-humidified when exposed to consistently high moisture levels, typically in regions with humidity levels of 80-90%, or over extended periods in areas where the humidity is medium-high (60-70%). Over-humidifying can also occur when owners attempt to combat dryness by using soundhole humidifiers excessively..

Though high humidity usually doesn’t cause cracks like low humidity can, it can still have detrimental effects on your guitar. The most common issues include:

• Swollen wood: This can lead to glue joints failing, finish lifting, and neck angles being distorted.
• Cosmetic damage: Distortions in the wood may remain even after repairs, leaving a permanent mark on the guitar.
• Dull sound: Excess moisture can add weight to the wood, causing the guitar to sound lifeless and flat.

Signs Your Guitar is Over-Humidified

Swollen body: The guitar may feel "puffy," and the body can appear swollen or warped.

High action: As the wood swells, the strings may sit higher off the fretboard, making the guitar difficult to play.

Dull tone: The excess moisture can weigh the wood down, affecting the resonance and making the sound lifeless.

How to Prevent Over-Humidification

Maintain a controlled environment: Invest in a good room humidifier or dehumidifier, depending on your local climate. Keep your guitar in an environment where humidity is controlled within the ideal range of 45-55%.

Use a hygrometer: These devices help you monitor the humidity in the room where your guitar is located. It is a small investment that can save you a lot of money on repairs. 

Store your guitar properly: Always keep your guitar in its case when not in use. Avoid leaving it in direct sunlight or in extreme conditions where the temperature and humidity fluctuate.