Is Humidity Bad for My Piano? What is Considered Safe?

humidity bad for piano

Humidity can affect your piano. According to the latest statistics, one in every 3,788 families owns a piano. Because of its high costs, it’s important for a piano owner to know how to take care of it, and what to do about humidity.

Humidity can be quite bad for your piano. There are several parts of your piano that are sensitive to humidity, such as felt, leather, precision wooden components, and cloth.  Humidity can also cause tuning problems, rusted internal components, and keys that stick.

With an acoustic piano costing thousands of dollars, protecting it should be at the top of your list of things to do to care for your piano. The good news is that you can easily make sure that the humidity doesn’t ruin your piano or the music it produces with a few simple tips.

But First, How Does Humidity Affect Your Piano?

If you think about it, water can be damaging to metal and wood, which are the top materials used for your piano. Water suspended in air, unfortunately, is not an exception when it comes to pianos. Your instrument is made up of components that are particularly sensitive to humidity, such as wood, felt, leather, and cloth.

Tuning and Regulation Problems

Humidity can swell or shrink your piano’s soundboard. This soundboard is made of a very thin piece of wood, that’s around three-eighths of an inch or around 9.5 millimeters. The soundboard acts as your piano’s speaker, and the strings of the piano pass through the slightly-crowned soundboard and connected to it by the bridge.

When your piano is exposed to too much moisture, the crown of the soundboard expands. This expansion will push the bridge harder against the strings, which will be stretched more tautly.

Tighter strings produce higher pitches. What will happen is that your piano will produce higher pitches in the middle octaves. The bass and treble will probably be unaffected, or it will be harder to detect.

Too much humidity can also lead to dull hammer action, as well as unclear tones. It can also cause keys to stick and internal parts to rust.

As such, putting your piano in a room where it’s too humid is a surefire way to ruin the sound that the instrument produces.

When It’s Too Dry

If there is low relative humidity, it can also affect your piano’s tuning as well.  Dryness can shrink the soundboard, resulting in drops in the pitch. The effect is much more pronounced in the keys set in the middle of the piano.

However, more than just having problems with the pitch and tuning, the bigger problem is when the piano’s area is prone to rapid fluctuations in humidity and moisture. Drastic changes can cause the very thin soundboard to expand and then contract, and might eventually break it.

Other Problems Caused by Humidity

Humidity can also affect the piano’s action, which is when you strike the keys right causing the hammers to strike the strings.  If the air is overly moist, the keys might be slow to respond when you press them. They may even become stuck.

If the air is too dry, the key may produce a rattling noise that is quite audible. Then there’s also the effects of humidity on the piano strings itself. 

These strings are coiled around the tuning pins that are, in turn, fixed into the pin block.  These pins fit snugly into the pin block, which allows makes it possible for the piano to be in tune for a long time.

If there is very low humidity, the pinblock will shrink, and the pins will become loose. This might mean that you will need to have your piano tuned soon.  It might also cause more serious damage, which will require to replace the whole pinblock.

In areas where humidity fluctuates from low to high, the piano strings and the tuning pins might rust.

How Do You Protect Your Piano from Excessively High or Low Moisture?

Now that you know that humidity can affect wood and other components of your piano, your first line of action should be to keep the humidity levels constant.

Protect Your Piano From Humidity
  • Don't place your piano in areas with:
    • High temperature fluctuations
    • High humidity fluctuations
    • Direct sunlight
  • Within your home, regulate the humidity:
    • Use a hygrometer to measure humidity.
    • Use a humidifier to raise humidity.
    • Use a dehumidifier to lower humidity.
  • If you have heated floors, use a rug or caster cups.

You will need to keep your piano away from places that experience extreme changes in temperature and humidity, such as cooling vent, radiators, heaters, doors, windows, and stoves.  

Further, don’t place your piano in an area where it gets hit with direct sunlight. Or near doors and windows that are susceptible to changes in the temperature outside. In houses that are not properly insulated, place your piano in a room where there are interior walls, rather than exterior walls that can get heated up or cooled down by the weather. 

You should also control the humidity within your home. For most places in the United States, winter often brings with it low relative humidity, while there is very high humidity during summer or spring. The best way to measure changes in relative humidity, however, is to buy a good wall hygrometer, such as this hygrometer and thermometer.

Keep the relative humidity anywhere from 45 percent to 70 percent. If the air is too dry, you can use a room humidifier to balance it out. Getting a room humidifier such as this highly rated Ultrasonic Cool Mist HumidifierHumidifier helps. 

To lower the humidity, use a dehumidifier that will pull the moisture out of the air, like this portable and quiet dehumidifier on Amazon.

What’s more, some things you can do may not cost you anything at all. For one, you can close the window when humidity rises. If you’re working with a tight budget, you might want to put indoor plants inside your piano room. These plants can help release water vapor through their leaves and can help purify the air inside the room.

You can also leave the key lid open sometimes if your piano is in a humid or darkroom. Doing so will encourage air circulation, dry up the components, and prevent the growth of molds inside the piano.

What’s more, if you have heated floors, you might want to use a large enough rug that will help protect your piano from the extreme heat and low humidity. These rugs should cover all three or four of your piano’s legs, as well as the middle. You may also consider putting caster cups.

If the air is too humid in the winter, you will want to keep your home evenly heated.

Lastly, it’s important to note that you should be focusing not only on the exact humidity or temperature in the room but also on preventing the fluctuations in the humidity levels.  Your piano will be able to withstand damage if humidity levels rise or fall slowly, but it can be damaged by sudden increases or decreases in moisture in the air.

Get the Right Humidity for Protecting Your Piano

While recommendations differ on what the right level of humidity is, the common advice is to keep relative humidity between 45 and 70 percent. This will help you avoid expanding or shrinking different wooden parts inside your piano that can affect how it sounds.  It will also help you avoid damaging your piano, which may mean expensive repairs and replacements.

Hopefully this information will help you extend the life of your piano and also save you money on repairs.

We have lots of other articles and tips specifically for pianos; make sure to check those out along with our recommended piano gear.

Josh Olswanger

I've been playing and writing music since the age of 13. My father is a piano tuner/technician of 40 years, and I've been musically involved in all aspects from composing, to recording, producing and playing live for most of my life. I've always had a fascination and appreciation for all types of music and musical instruments, so creating this site is a perfect outlet to share my knowledge.

Related Posts